Patent application title: Registry Method and Control System for Dea Schedule II-V Medicines

Abstract:

The present invention provides compositions and methods for synthesizing
labeled drugs. The present invention further provides methods for
preventing or stopping prescription drug abuse for all agents registered
as a Drug Enforcement Agency (DEA) schedule II through schedule V
medications. According to the present invention, methods are provided for
monitoring patient compliance with prescribed drug treatment. The present
invention also provides methods for facilitating a replacement
prescription when a patient is left without access to their prescribed
drug. Furthermore, the present invention provides a method to improve
employee compliance with an employer's drug policies via either a
voluntary or compulsory system for enhanced drug testing.

Claims:

1. An isotopically labeled compound represented by general Formula I:
##STR00039## wherein,at least two of the atoms of the structure are
2H, 13C, 15N, 18O, or a mixture thereof;R1 is
selected from chlorine, fluorine and nitro;R2 is selected from
hydrogen, fluorine, or chlorine;R3 is selected from hydrogen,
deuterium, carboxy (--COOH) or hydroxy;R4 is selected from no
substituent or oxygen;X1 is selected from oxo, 18oxo, sulphur
(═S) or aminomethyl (--NHCH3);X2 is selected from no
substituent, hydrogen, methyl,
--CH2CH2N(CH2CH3)2, trifluoroethyl
(--CH2CF3), or methylenecyclopropyl ##STR00040## X1 and
X2 together represent the bridge ##STR00041## when X2 is no
substituent or X1 is amino methyl (--NHCH3), there is a double
bond between nitrogen-1 and carbon-2 and a single bond between carbon-2
and X2; andwhen X1 is oxo or 18oxo, or X1 and X2
together represent the bridge ##STR00042## there is a single bond between
nitrogen-I and carbon-2 and a double bond between carbon-2 and
X2;and pharmaceutically acceptable salts and solvates thereof.

2. The compound of claim 1, wherein the compound has the structure:
##STR00043##

3. The compound of claim 1, wherein the compound has the structure:
##STR00044##

4. The compound of claim 1, wherein the compound has the structure:
##STR00045##

5. The compound of claim 1, wherein the compound has the structure:
##STR00046##

6. The compound of claim 1, wherein the compound has the structure:
##STR00047##

7. A method for producing the compounds of Formula I, wherein there is a
C--N single bond between nitrogen 1 and carbon 2, X1 is oxygen and
there is a C═O double bond between X1 and carbon 2, and X2
is hydrogen and R3 is hydrogen and R4 is no substituent,
comprising:(a) condensing a compound of Formula B1: ##STR00048##
whereinthe compound B1 contains from zero to at least one isotopic label
comprising 2H, 13C, 15N, 18O, or a mixture thereof;R1
is selected from chlorine, fluorine or nitro; andR2 is selected from
hydrogen, fluorine, or chlorine,with an isotopically labeled compound B2:
##STR00049## whereinat least one atom labeled with "*" is an isotopic
label selected from the group consisting of 13C, 15N, 18O,
2H, and a mixture thereof;Y is a leaving group;P1 is an amine
protecting group;(b) then removing the protecting group P1 to
produce a compound of formula B3: ##STR00050## whereincompound B3
contains at least two isotopic labels; and(c) then intramolecularly
dehydrating B3 to form a compound of formula B4; ##STR00051##
whereincompound B4 contains at least two isotopic labels.

8. A method for producing compounds of Formula I, wherein there is a C--N
single bond between nitrogen 1 and carbon 2, X1 is oxygen and there
is a C═O double bond between X1 and carbon 2, and R3 is
hydrogen, R4 is no substituent, and X2 is methyl (--CH3),
--CH2CH2N(CH2CH3)2, trifluoroethyl
(--CH2CF3), or methylenecyclopropyl ##STR00052## comprising:(a)
treating an isotopically labeled compound B4 with a strong base; and(b)
then treating the compound with an alkyl halide to produce a compound of
formula B5: ##STR00053## whereincompound B5 contains at least two
isotopic labels.

9. A method for producing compounds of Formula I, wherein there is a C--N
single bond between nitrogen 1 and carbon 2, X2 is hydrogen or
methyl, X1 is oxygen and there is a C--O double bond between X1
and carbon 2, and R3 is hydroxy, and R4 is no substituent,
comprising:(a) reacting a compound of Formula B5: ##STR00054##
whereincompound B5 contains at least two isotopic labels,with an electron
poor peroxyacid;(b) then treating the resulting product with a compound
of formula B6; ##STR00055## whereinR1 and R2 are independently
selected from C1-C6 alkyl; and(c) then saponifying the ester
intermediate

10. A method for producing compounds of Formula I, wherein there is a C--N
single bond between nitrogen 1 and carbon 2, X1 and X2 together
represent the bridge ##STR00056## and R3 is hydrogen and R4 is
no substituent, comprising:(a) treating a compound of Formula B7:
##STR00057## whereincompound B7 contains at least two isotopic
labels,with a base;(b) then reacting the compound with
diethylchlorophosphate; and(c) then reacting the compound with a compound
of formula B8 ##STR00058##

11. An isotopically labeled compound represented by Formula II:
##STR00059## whereinat least two of the atoms of the structure are
present as isotopes 2H, 13C, or 15N;R1 is selected
from hydrogen or methyl,and pharmaceutically acceptable salts, solvates,
and mixtures thereof.

12. The compound of claim 11 wherein the compound is from: ##STR00060##

13. A method for producing the compounds of Formula II, wherein R5
has the meaning of hydrogen or methyl, comprising:reducing a compound of
Formula A1 ##STR00061## whereincompound A1 contains at least two isotopic
labels; andX3 is hydroxy or oxo.

14. A method for producing compounds of Formula II, wherein R5 has
the meaning of hydrogen, comprisingreducing a compound of Formula A2:
##STR00062## whereincompound A2 contains at least two isotopic labels;
andthe nitroalkene can be present in the E or Z form or a mixture
thereof.

15. A method for producing compounds, of Formula II, wherein R5 has
the meaning of hydrogen or methyl, comprising:reducing a compound of
Formula A3 ##STR00063## whereincompound A3 contains no or at least two
isotopic labels; andin the presence of a NHR6, wherein R6 is
selected from hydrogen or methyl.

16. A method for producing compounds of Formula I, wherein R has the
meaning of methyl, reducing a compound of formula XV ##STR00064##
whereincompound A4 contains no or at least two isotopic labels.

17. An isotopically labeled compound of Formula III: ##STR00065##
whereinat least two of the atoms in the structure are 2H, 13C,
15N, 18O, or a mixture thereof.

18. A method for preventing or stopping drug abuse, which comprises:(a)
prescribing a labeled drug to a patient;(b) recording the labeled drug
prescription in a registry accessible to providers;(c) testing a fluid or
tissue sample from the patient for the presence of labeled drug and
unlabeled drug; and(d) refusing to prescribe the drug to a patient
testing positive for unlabeled drug or a labeled drug not recorded in the
registry.

19. A method for preventing or stopping drug abuse, which comprises:(a)
accessing a patient's prescription in a registry;(b) testing a fluid or
tissue sample from the patient for the presence of labeled and unlabeled
drug if the patient has a current prescription for a labeled drug
recorded in the registry; and(c) refusing to prescribe the drug to a
patient who tests positive for the presence of unlabeled drug and has a
current prescription for a labeled drug recorded in the registry.

20. A method for monitoring patient compliance with a prescription for a
controlled pharmaceutical agent, which method comprises:(a) prescribing a
controlled pharmaceutical agent that has been labeled to a patient;(b)
recording the labeled controlled pharmaceutical agent prescription in a
registry;(c) testing a fluid or tissue sample from the patient for the
presence of labeled and unlabeled controlled pharmaceutical agent; and(d)
identifying a patient who tests negative for the presence of labeled
controlled pharmaceutical agent;wherein the patient who tests negative
for the presence of labeled controlled pharmaceutical agent is a
non-compliant patient.

21. A method for monitoring patient compliance with a prescription for a
DEA schedule II to V drug, which method comprises:(a) accessing a
patient's prescription information record in a registry;(b) testing a
fluid or tissue sample from the patient for the presence of labeled and
unlabeled drug; and(c) identifying a patient with a current prescription
for a labeled drug recorded in the registry and who tests negative for
the presence of labeled drug;wherein the patient with a current
prescription for a labeled drug recorded in the registry who tests
negative for the presence of labeled drug is a non-compliant patient.

22. A method for facilitating replacement drug prescription by a provider,
which method comprises:(a) accessing a registry;(b) prescribing a
replacement drug prescription to a patient with a current labeled drug
prescription recorded on the registry;wherein the labeled drug prescribed
and recorded in the registry is not immediately available to the patient.

23. A method for safely tapering a drug, which method comprises:(a)
prescribing a taper labeled drug regimen to a patient;(b) recording the
taper labeled drug regimen in a registry;(c) testing the patient's tissue
or body fluid for unlabeled drug and labeled drug;(d) identifying a
patient who is properly adhering to the taper labeled drug regimen when
the patient tests positive for a labeled drug appropriate to the taper
regimen at the time of testing; or(e) identifying a patient who is not
properly adhering to the taper labeled drug regimen when the patient
tests positive for an unlabeled drug or a labeled drug that is not
appropriate to the taper regimen at the time of testing or who tests
negative for unlabeled drug and labeled drug.

24. The method of any one of claims 18 to 21 or 23, wherein the testing
step comprises testing the fluid or tissue sample for the presence of
labeled drug using gas or liquid chromatography and mass spectrometry.

25. The method of any one of claims 18 to 22, wherein the labeled drug is
a benzodiazepine.

26. The method of any one of claims 18 to 22, wherein the labeled drug is
an amphetamine.

27. The method of any one of claims 18 to 22, wherein the labeled drug is
methylphenidate.

28. The method of any one of claims 18 to 22, wherein the labeled drug is
an opioid.

29. A pharmaceutical composition comprising an isotopically labeled
compound of any one of claims 1 to 6, 11, 12, or 17 and a
pharmaceutically acceptable carrier.

30. An isotopically labeled compound represented by general Formula IV:
##STR00066## whereinat least one of the atoms of the structure is
2H, 13C, 15N, 18O, or a mixture thereof;R1 is
selected from hydrogen, deuterium, --OH, or 18OH;R2 is selected
from hydrogen or deuterium;R3 is selected from hydrogen or
deuterium; orR2 and R3 are not present and there is a C--C
double bond between carbon 2 and carbon 3;R4 is selected from
hydrogen or deuterium;R5 is selected from --OH or 18OH;R6
is selected from --H, --CH3 or --.sup.13CH3; orR4 and
R5 together form oxo (═O or ═18O); andpharmaceutically
acceptable salts, solvates, and mixtures thereof

32. A pharmaceutical composition comprising a mixture of a drug having
different labels in a specified ratio and a pharmaceutically acceptable
carrier.

33. The method according to any one of claims 18 to 23, wherein the
labeled drug comprises a mixture of drugs having different labels in a
specified ratio.

34. A method for prescribing a labeled controlled drug to a patient, which
comprises(a) creating a drug registry containing information on
prescriptions written for controlled drugs and the identity of the
patient receiving such prescriptions,(b) recording all controlled drug
prescriptions in the registry,(c) interrogating the drug registry for
information on the patient, and(d) prescribing a labeled controlled drug
to a patient only if the patient does not have an unexpired prescription
for the same controlled drug recorded in the registry.

35. The method of claim 34, further comprising testing tissue or body
fluid of the patient for the presence of labeled and unlabeled versions
of the controlled substance before the prescribing step.

36. The method of claim 35, further comprising recording the test results
in the registry.

37. A method for prescribing a labeled controlled drug to a patient, which
comprises(a) creating a drug registry containing information on
prescriptions written for controlled drugs and the identity of the
patient receiving such prescriptions;(b) recording all controlled drug
prescriptions and patient identities in the registry,(c) interrogating
the drug registry for information on the patient,(d) testing the
patient's tissue or body fluid for the presence of labeled or unlabeled
controlled drug, and(e) prescribing a labeled controlled drug to a
patient only if the patient does not have:(i) a positive test result for
an unlabeled controlled drug or a labeled controlled drug that is not
recorded on the registry, or(ii) an unexpired prescription for the same
controlled drug recorded in the registry.

39. A method for prescribing a labeled controlled drug to a patient, which
comprises(a) creating a drug registry containing information on
prescriptions written for controlled drugs and the identity of the
patient receiving such prescriptions,(b) recording all controlled drug
prescriptions in the registry,(c) interrogating the drug registry for
information on the patient,(d) comparing a prescription for a labeled
controlled drug with the registry information on the patient; and(e)
issuing the prescription only if the patient does not have an unexpired
prescription for the same controlled drug recorded in the registry.

43. The isotopically labeled compound of claim 30, wherein at least one of
the atoms of the structure is 2H, 18O, or a mixture
thereof;R1 is selected from hydrogen or deuterium;R2 and
R3 are not present and there is a C--C double bond between carbon 2
and carbon 3;R4 is selected from hydrogen or deuterium;R5 is
selected from --OH or 18OH;R6 is H; andpharmaceutically
acceptable salts, solvates, and mixtures thereof.

44. The isotopically labeled compound of claim 30, wherein at least one of
the atoms of the structure is 2H or 18O;R1 is selected
from hydrogen or deuterium;R2 is selected from hydrogen or
deuterium;R3 is selected from hydrogen or deuterium;R4 and
R5 together form oxo (═O or ═18O);R6 is H;
andpharmaceutically acceptable salts, solvates, and mixtures thereof.

45. A pharmaceutical composition comprising an isotopically labeled
compound of any one of claims 40-44 and a pharmaceutically acceptable
carrier.

46. The method of any one of claims 18 to 22, wherein the labeled drug is
selected from the group consisting of buprenorphine, zolpidem, and
tramadol.

47. The method of claim 28, wherein the opioid is morphine or
hydromorphone.

48. The compound of claim 30, wherein 2 or more atoms of the structure are
2H, 13C, 15N, 18O, or a mixture thereof.

52. The isotopically labeled compound of claim 30, wherein 2 or more atoms
of the structure are 2H, 13C, 15N, 18O, and mixtures
thereof.

53. A method for identifying a non-compliant patient who does not comply
with a prescription for medication, comprising:(a) prescribing a
medication to a patient for a period of time comprising a first
predetermined interval and a second predetermined interval wherein the
first predetermined interval and second predetermined interval are
consecutive;(b) providing the patient with a supply of the medication
adequate to cover the period to time, wherein the supply comprises units
of the medication having a plurality of different labels;(c) instructing
the patient to self-administer the labeled units having a first label
during the first predetermined time;(d) instructing the patient to
self-administer the labeled units having a second label during the second
predetermined time, the second label being different from the first
label;(e) testing the patient for the presence of the first label during
the second predetermined interval;(f) testing the patient for the
presence of the second label during the second predetermined interval;
and(g) identifying a patient testing negative for the presence of the
first label and the second label as non-compliant with the prescription
medication for the period of time.

54. The method of claim 53, wherein the period of time is about one month.

Description:

[0001]This application claims priority to U.S. provisional application No.
60/656,232, filed Feb. 24, 2005, the contents of which are hereby
incorporated by reference in their entirety.

FIELD OF THE INVENTION

[0002]The present invention relates to compositions and methods for
synthesizing labeled drugs. The present invention further relates to
methods for preventing or stopping prescription drug abuse for all agents
registered as a Drug Enforcement Agency (DEA) schedule II through
schedule V medications. Further, the present invention provides methods
for monitoring patient compliance with prescribed drug treatment. The
present invention also provides methods for facilitating a replacement
prescription when a patient is left without access to their prescribed
drug. Furthermore, the present invention provides a method to improve
employee compliance with an employer's drug policies via either a
voluntary or compulsory system for enhanced drug testing.

BACKGROUND

[0003]Abuse of prescribed drugs such as benzodiazepines, amphetamines,
amphetamine-like drugs, and opioid narcotics pose a major health risk and
numerous enforcement problems in the United States and worldwide.

[0004]Benzodiazepines are anxiolytic (anxiety-relieving), hypnotic
(sleep-inducing) and increase a patient's seizure threshold.
Benzodiazepines are prescribed for medical conditions including anxiety,
insomnia, alcohol withdrawal, seizures and as anesthetic agents given
prior to and during surgery. The class of benzodiazepines contains many
different medications. A partial list includes: midazolam (Versed),
triazolam (Halcion), alprazolam (Xanax), lorazepam (Ativan),
chlordiazepoxide (Librium), diazepam (Valium), bromazepam (Lexotan),
flunitrazepam (Rohypnol, the "date-rape" drug), flurazepam (Dalmane),
nitrazepam (Mogadon), oxazepam (Serenid), and temazepam (Restoril,
Normison, Euhypnos). Benzodiazepines act on the central nervous system
through interactions with gamma amino butyric acid (GABA) receptors. A
physician, or para-professional, must hold a current and valid DEA
certificate and be in good standing to prescribe a benzodiazepine.
Benzodiazepines, while widely prescribed for a number of indications, are
especially prone to substance abuse because they are rapidly acting
anxiolytic agents.

[0005]The DEA recognizes the high propensity for abuse of benzodiazepines
and has thus classified benzodiazepines as schedule IV medications.
Benzodiazepine abusers often engage in "doctor-shopping," i.e., obtaining
overlapping benzodiazepine prescriptions from different physicians.
Doctors' prescriptions are the primary source of illicit benzodiazepines
(Ashton H, Drugs and Dependence. 2002; 197-212 (Harwood Academic
Publishers)). Benzodiazepines are often mixed with alcohol and commonly
form part of a polysubstance abuse pattern, which can include heroin,
opioids, cocaine and amphetamines (see Ashton). When benzodiazepines are
mixed with alcohol, the intoxicating effects are not merely additive, but
synergistic, and pose significant additional safety risks to individuals
operating motor vehicles, passengers in their vehicles and those who
share the road with them.

[0006]Amphetamines are used to treat medical conditions including
Attention Deficit Disorder (ADD), Attention Deficit Hyperactivity
Disorder (ADHD), narcolepsy, depression, and historically were used as
appetite suppressants or weight loss medications. The family of compounds
derived from amphetamine (Benzedrine) include dextroamphetamine
(Dexedrine), methamphetamine (Desoxyn), benzphetamine (Didrex) and a
number of others.

[0007]Methylphenidate (Ritalin) is an amphetamine-like drug prescribed for
the treatment of the same disorders as amphetamines, perhaps with a
somewhat lower probability of producing addictions. Both methylphenidate
and its analogues, as well as the amphetamines and their analogues, are
frequently prescribed to children and unfortunately are often used and
abused by older siblings and others. On many college campuses, university
students have found that crushing and snorting methylphenidate and
amphetamines can produce cocaine-like euphoria.

[0008]Long-term, high dosage use of amphetamines and amphetamine-like
drugs can result in symptoms of anxiety, panic, hallucinations and
paranoia. Because these agents are sympathomimetic, they also act to
increase heart rate, blood pressure and, at times, insomnia. Amphetamines
and amphetamine-like drugs are extremely psychologically addictive
because they increase brain dopamine levels and specifically target the
brain's reward center, i.e., the nucleus accumbens.

[0009]A publication, Monitoring the Future Survey (MTF), funded by the
National Institute on Drug Abuse, National Institutes of Health, and
Department of Health and Human Services assesses the extent of drug use
among adolescents and young adults in the United States. The 2003 MTF
data on annual use indicate that 2.6% of 8th-graders abused Ritalin, as
did 4.1% of 10th-graders and 4.0% of 12th-graders.

[0010]Opioids are commonly prescribed for their effective analgesic
properties. Some of the medications that fall within this class include
morphine, codeine, oxycodone (OxyContin), propoxyphene (Darvon),
hydrocodone (Vicodin), hydromorphone (Dilaudid), and meperidine
(Demerol). In addition to their pain-relieving properties, some of these
drugs--for example, codeine and diphenoxylate (Lomotil)--can be used to
relieve coughs and diarrhea. Long-term use of opioids can lead to
physical dependence and addiction.

[0011]The methods of the present invention can stop or prevent
prescription drug abuse because a patient is denied access to a second,
overlapping prescription and doctor-shopping is effectively thwarted.
Prevention of drug abuse can be especially beneficial to the individual
and society because of the high rates of relapse following treatment for
drug abuse. For example, the rate of relapse following benzodiazepine
detoxification has been reported to be over 90 percent (Seivewright N and
Dougal W. Drug Alcohol Depend. 1993; 32:15-23; Seivewright et al., Int J
Drug Policy. 1993; 4:42-48).

[0012]Centralized databases for recording and monitoring prescription
medications have been proposed, see, e.g., U.S. Pat. No. 6,687,676.
Recordation in a database alone (without drug labeling) does not address
the problems of abuse in which the abuser receives drug from a third
party, unauthorized provider (e.g., a friend, a drug dealer), or an
unscrupulous or unknowing provider (e.g., an unknowing doctor). Use of a
database alone, would not allow a prescriber to discern whether the abuse
is occurring due to medications supplied by a third party or
unscrupulous/unknowing provider because medication from the two sources
can not be differentiated. The methods of the present invention would
allow identification of the source of the illicit medication because any
unlabeled medication in the patient's tissue or body fluid is evidence of
abuse.

SUMMARY OF TEE INVENTION

[0013]The present invention relates to labeled drugs, methods for
synthesizing labeled drugs and pharmaceutical compositions including
labeled versions of DEA schedule II to V drugs. In aspects of the present
invention, a labeled drug prescription is recorded in a registry. The
present invention further relates to methods for preventing or stopping
prescription drug abuse. Further, the present invention provides methods
for monitoring patient compliance with prescribed drug treatment. The
present invention also provides methods for facilitating replacement drug
prescription when a patient is left without access to their prescribed
drug.

[0014]In one embodiment, labeled benzodiazepines according to the present
invention are represented by general Formula I as follows:

##STR00001##

wherein,

[0015]At least two of the atoms of the structure are present as isotopes
2H, 13C, 15N, or 18O;

[0016]R1 is selected from chlorine, fluorine and nitro;

[0017]R2 is selected from hydrogen, fluorine, or chlorine;

[0018]R3 is selected from hydrogen, deuterium, carboxy (--COOH) or
hydroxy;

[0053]In one embodiment of the invention, a method for preventing drug
abuse is provided wherein a prescriber identifies a patient as a
potential abuser, prescribes a single, double, triple or higher multiple
of a labeled drug to the potential abuser, records the prescription on a
national registry, tests a tissue or body fluid (e.g., urine or blood) of
the potential abuser for the presence of unlabeled drug, and identifies
an abuser as an individual who tests positive for unlabeled drug.

[0054]In another embodiment of the invention, a method for monitoring
compliance with prescribed drug treatment is provided wherein a
prescriber prescribes a drug product in which one or more of the atoms
has been replaced with a labeled atom. According to the invention, one,
two, three or more atoms of a drug product may be replaced with a labeled
atom to enable rapid identification of the product. In another
embodiment, a drug product that has been labeled on two, three or more
atoms is administered to a patient, the prescription is recorded on a
national registry, and a tissue or body fluid (e.g., urine or blood) of
the patient is thereafter tested for the presence of labeled and
unlabeled drug. The test result identifies a non-compliant patient as an
individual who tests negative for the prescribed labeled drug.

[0055]The present invention further provides a method in which a
prescriber prescribes a drug that has been single, double or triple
labeled and wherein the patient is unaware of the number of labels on the
prescribed drug; the prescriber records the prescription in a registry;
the patient is tested for the presence of unlabeled drug and labeled
drugs having one, two, three or more labels; and a provider refuses to
re-prescribe the drug to a patient testing positive for unlabeled drug or
labeled drug having a number of labels different from the prescribed
labeled drug.

[0056]The invention further comprises a method for prescribing a labeled
controlled drug to a patient, which includes the steps of:

[0057](a) creating a drug registry containing information on prescriptions
written for controlled drugs and the identity of the patient receiving
such prescriptions,

[0058](b) recording all controlled drug prescriptions in the registry,

[0059](c) interrogating the drug registry for information on the patient,
and

[0060](d) prescribing a labeled controlled drug to a patient only if the
patient does not have an unexpired prescription for the same controlled
drug or another controlled drug of the same class (e.g., the controlled
drug and the another controlled drug are both opioids) recorded in the
registry.

[0061]In an embodiment of the invention, the results of a test on a
patient's tissue or body fluid for the presence of labeled or unlabeled
drug is recorded on the registry.

[0062]In another aspect of the present invention, a method is provided for
prescribing a labeled controlled drug to a patient, which includes the
steps of:

[0063](a) creating a drug registry containing information on prescriptions
written for controlled drugs and the identity of the patient receiving
such prescriptions;

[0064](b) recording all controlled drug prescriptions and patient
identities in the registry,

[0065](c) interrogating the drug registry for information on the patient,

[0066](d) testing the patient's tissue or body fluid for the presence of
labeled or unlabeled controlled drug, and

[0067](e) prescribing a labeled controlled drug to a patient only if the
patient does not have: [0068](i) a positive test result for an
unlabeled controlled drug or a labeled controlled drug that is not
recorded on the registry, or [0069](ii) an unexpired prescription for the
same controlled drug recorded in the registry.

[0070]In a further aspect of the present invention, a method is provided
for prescribing a labeled controlled drug to a patient, which includes
the steps of:

[0071](a) creating a drug registry containing information on prescriptions
written for controlled drugs and the identity of the patient receiving
such prescriptions,

[0072](b) recording all controlled drug prescriptions in the registry,

[0073](c) interrogating the drug registry for information on the patient,

[0074](d) comparing a prescription for a labeled controlled drug with the
registry information on the patient; and

[0075](e) issuing the prescription only if the patient does not have an
unexpired prescription for the same controlled drug recorded in the
registry.

[0076]A drug can be labeled with a stable isotope according to the methods
of the present invention by identifying suitable sites for isotope
substitution such that substitution does not affect the activity of the
drug. Following identification of a suitable substitution site(s),
isotopes are substituted onto the drug by methods well known in the art
as disclosed in, for example, Voges et al., Proceedings of the
International Symposium, 5th Strasbourg, June 20-24 (1995):1-26; and
Mertel H, Drug Fate and Metabolism 1979; 3:133-191.

[0077]Synthesis of a labeled drug according to the methods of the present
invention includes incorporation of isotopically labeled fragments of a
drug that can be derived from commercially available reagents containing
one or more heavy atom isotopic labels with greater than 90% isotopic
purity. The isotopic labels are incorporated at metabolically stable
sites of the drug so that they are retained on the compound while it is
in the tissues or body fluids of a patient (e.g., the labels are retained
on the compound when the compound is in the blood stream or when it
passes from the body in the urine). Stable isotope labels 2H, 13C, 15N,
17O, 18O, 33S, 34S, and 36S are preferred. Especially preferred stable
isotope labels are 13C, 15N, 17O and 18O. The cost of synthesizing
labeled drugs according to the present invention can be contained by
selecting drugs, which are dosed in small amounts of active agent (i.e.,
less than 250 mg). Cost can further be contained by the economies of
scale involved when large amounts of labeled drug are produced.

[0078]The present invention provides a method for identifying a
non-compliant patient who does not comply with a prescription for
medication, which includes the steps of:

(a) prescribing a medication to a patient for a period of time comprising
a first predetermined interval and a second predetermined interval
wherein the first predetermined interval and second predetermined
interval are consecutive;(b) providing the patient with a supply of the
medication adequate to cover the period to time, wherein the supply
comprises units of the medication having a plurality of different
labels;(c) instructing the patient to self-administer the labeled units
having a first label during the first predetermined time;(d) instructing
the patient to self-administer the labeled units having a second label
during the second predetermined time, the second label being different
from the first label;(e) testing the patient for the presence of the
first label during the second predetermined interval;(f) testing the
patient for the presence of the second label during the second
predetermined interval; and(g) identifying a patient testing negative for
the presence of the first label and the second label as non-compliant
with the prescription medication for the period of time.

[0079]In a preferred embodiment, the period of time is about one month.

[0097]As used herein, "drug," "schedule drug," "controlled drug,"
"controlled pharmaceutical agent" or "controlled substance" refers to a
prescribed medication having the potential for abuse (i.e., a DEA
schedule II through V medication). A drug according to the present
invention includes, for example, medications in the benzodiazepine,
amphetamine, amphetamine-like, and opioid classes.

[0098]As used herein, "label" refers to a tag or marker that is added onto
or made part of the molecular structure of a drug, which permits a
labeled drug to be distinguished from an unlabeled drug in an
individual's tissue or body fluid but does not affect the pharmacologic
activity of the drug. A preferred label according to the present
invention is a stable isotope.

[0099]A "labeled drug" as used herein refers to a drug having at least one
label (e.g., single or double isotope labeled diazepam) or a mixture of a
drug having different labels in a specified ratio (e.g., a mixture of
single labeled diazepam and double labeled diazepam in a 9:1 ratio).

[0100]As used herein, the term "abuse" refers to use of a drug (e.g., a
benzodiazepine) in a greater than prescribed amount or frequency. An
"abuser" is an individual who abuses a drug.

[0101]A "provider," as used herein is a doctor or anyone legally
authorized to prescribe a drug, e.g., a benzodiazepine.

[0102]A "prescriber," as the term is used herein, is a provider who has
written a prescription for a drug, e.g., a benzodiazepine, for a
particular patient.

Labeled Drugs

[0103]According to the present invention, a drug is labeled so that it can
be identified when a specimen of a tissue or body fluid is removed from a
patient receiving the labeled drug (i.e., by assaying in a sample of the
patient's tissue or body fluid) and readily distinguished from an
unlabeled version of the same drug. More particularly, the drug is
labeled to contain an isotopic label(s) at a metabolically stable
position(s) such that the labeled drug has the same biological effects as
unlabeled drug. The isotopes according to the present invention are
stable and inert. Preferably, the isotopes are rare. Isotopes according
to the present invention include isotopes of hydrogen, carbon, nitrogen,
oxygen, and sulfur (e.g., 2H, 13C, 15N, 17O and 18O).

[0104]A labeled drug according to the present invention can be selected
and synthesized by a method, which includes the steps of:

[0105](a) selecting a drug that is medicinally useful but can be abused
(i.e.: any of the schedule II through V drugs);

[0106](b) selecting atoms in the drug compound that are metabolically
stable, i.e., atoms that are retained in the drug compound when the drug
is in the blood stream and urine;

[0107](c) selecting a known synthesis for the drug that includes reagents
that allow the addition of non-radioactive isotope labels at an
intermediate step in the synthesis;

[0108](d) adding the labeled reagent;

wherein a labeled drug is synthesized.

[0109]Introduction of the label late in the synthesis is more cost
effective than introduction of the label early in the synthesis of the
labeled drug.

[0110]The isotope labels should be inserted with high fidelity (about 90%
or greater). Preferably, the isotopically labeled reagents are
commercially available with high purity of the isotope label.
Isotopically labeled reagents containing 2H, 13C, 15N, 17O, and 18O are
preferred. One isotope label in a drug can be used according to the
present invention. More than one isotope label in a drug is preferred
because the mass signature of the labeled drug will be more distinct for
a drug with more than one label compared to a drug with one label.

[0111]Different labeled versions of the same drug can be mixed together to
create uniquely identifiable mixtures. Thus, a very large number of
uniquely identifiable isotope formulations can be created. For example,
singly labeled oxycodone can be mixed at a 9:1 ratio with doubly labeled
oxycodone, this would provide a mass signature in a drug test that would
make this 9:1 mixture distinguishable from an 8:2 or 7:3 mixture. The
only limit to the number of uniquely identifiable labeled formulations is
the precision to which mass spectrometry can distinguish between isotope
mixtures. The ratio of the labeled versions of a drug can be used as a
code in conjunction with the national registry system that is part of the
present invention.

[0112]The present invention provides labeled drugs and methods for
synthesizing labeled drugs. A preferred label is a stable isotope. In an
embodiment of the invention, it is advantageous to include at least one
isotope label in a drug. The inclusion of isotopes in a drug increases
the cost of synthesis, which can discourage the production of labeled
illicit or "street" drugs.

[0113]Preferred labeled drugs according to the present invention are
labeled drugs in the benzodiazepine, amphetamine, amphetamine-like (e.g.,
methylphenidate), and opioid class.

Registering a Labeled Drug

[0114]A registry according to the present invention is a database
accessible to providers of drugs wherein data relating to the
prescription of a labeled drug can be recorded and accessed by a provider
or pharmacist. The registry includes a host system capable of selectively
receiving, storing and dispensing prescription information; and a
plurality of provider systems remote from the host system, which are
capable of receiving and inputting prescription information into the host
system. The provider system is also capable of retrieving prescription
information from the host system. The registry can be accessed, for
example, using a public telephone line with a coded connection (e.g., a
password). The registry is constructed to protect patient privacy and is
preferably compliant with existing law relating to patient privacy and
right of access (e.g., Health Insurance Portability and Accountability
Act ("HIPAA")). Access to a registry according to the present invention
is limited to providers and, optionally, pharmacists, as well as any
other individuals authorized by law (e.g., law enforcement officers).
Methods for ensuring privacy are well known and include, for example,
providing unique patient identifiers. For example, when a patient enters
the registry he is assigned a unique identifying number or alphanumeric
code that can be used to uniquely identify him and to distinguish him
from other registry participants. Construction and maintenance of a
registry according to the present invention is well known as provided in,
for example, U.S. Pat. No. 6,687,676.

[0115]The data required to be entered by a prescriber is preferably kept
to a minimum to encourage provider compliance. Such minimum data includes
a patient's name or identifier, a prescriber's name or identifier, the
start date of the prescription (i.e., the date the drug is dispensed),
the drug prescribed, the dosage and frequency, duration of treatment, and
the indication for the prescription. In an embodiment of the invention, a
patient would have to show a provider, as well as a pharmacist, a valid
state or federal form of identification in order to obtain and fill a
prescription. Additional forms of identification can include, for
example, unique identifiers such as fingerprints, retinal scans, DNA
fingerprinting or other biometric identifiers. A unique identifier
decreases the likelihood of a patient submitting multiple identities
within the registry system.

[0116]Any physician can interrogate the registry in order to determine if
a new patient had previously received a prescription form another doctor
for the same DEA schedule II to V drug. The interrogation can be via the
patient's number or through use of the patient's assigned "identifier" or
password on the system.

[0117]In an embodiment of the present invention, a pharmacist can access
the registry, and a labeled drug prescription will not be filled and
dispensed unless the prescription has been recorded in the registry.

[0118]In another embodiment of the present invention, a pharmacist can
access the registry, and a labeled drug prescription will not be
dispensed for a patient if a current labeled drug prescription for the
patient appears in the registry. According to this aspect of the present
invention, concurrent dispensing of the same or similar drugs can be
prevented.

[0119]In another aspect of the present invention, a pharmacist can access
the registry and record in the registry the date, and optionally the
time, when a drug prescription is being filled. This will "start the
clock" on the prescription

Detecting a Labeled Drug

[0120]An isotopically labeled drug can be detected and distinguished from
an unlabeled drug by any method, which can detect labeled and/or
unlabeled drug in an individual's tissue or body fluid (e.g., blood or
urine) and distinguish the molecular weight of the labeled and unlabeled
drug. In an aspect of the invention, a detection method can distinguish
drugs having different labels (e.g., one isotope label versus two isotope
labels versus three isotope labels). In another aspect of the invention,
a detection method can distinguish drugs containing different mixtures of
labels (e.g., a 9:1 mixture of singly and doubly labeled oxycondone
versus a 1:1 mixture of singly and doubly labeled oxycondone).

[0122]Detection of labeled and unlabeled drugs using GC/MS or LC/MS would
be carried out on a sample of a few milliliters of blood or urine or some
other matrix such as sweat, saliva, meconium, or a nail. Prior to GC/MS
or LC/MS a sample preparation step is often carried out that may involve
cleavage of conjugates, isolation, and derivatization, preceded or
followed by cleanup steps. After the sample preparation step, an
isolation step involving liquid-liquid extraction (LLE) or by solid-phase
extraction (SPE) is carried out to extract the organic components from
the prepared sample. One method of extraction is to insert a Twister®
stir bar into the prepared liquid sample and stir for a few minutes. The
stir bar is removed, washed with water, dried and heated to volatilize
the organics. The volatile organic compounds are injected into a GC/MS
and run for about 30 minutes.

[0123]Gas chromatography (GC) separates drugs in a sample by passing the
sample through a column with a stream of helium gas. The inside surface
of the column is coated with wax. The wax slows down the drugs as they
pass through the column so that some drugs take longer than others to
reach the end of the column. As the drugs exit the column, the mass
spectrum detector records the fragmentation fingerprint of the drugs.
Drug identification is based on its transit time through the column and
molecular fragmentation fingerprint. These two unique characteristics
provide precise identification (See Forensic Applications of Mass
Spectrometry, by Jehuda Yinon ISBN: 0849382521; Advances in Forensic
Applications of Mass Spectrometry, by Jehuda Yinon, ISBN: 0849315220).

[0124]Labeled and unlabeled drug emerge from the gas chromatograph at the
same time, but are distinguishable by mass spectroscopy. For example, the
mass of unlabeled alprazolam ("rA") is 308 Daltons. Using the technique
of gas chromatography-mass spectrometry, unlabeled alprazolam is detected
as a mass envelope of m/e: 308.08 (100.0%), 310.08 (32.2%), 309.09
(18.5%), 311.08 (6.4%), 310.09 (1.6%), 309.08 (1.5%). Under the same
conditions, singly labeled alprazolam is detected with the same retention
time as unlabeled alprazolam but with a mass envelope of m/e: 309.09
(100.0%), 311.09 (32.2%), 310.09 (19.9%), 312.09 (6.0%), 311.10 (1.6%).
The fragment of labeled alprazolam will be detected with the largest peak
at m/e 274.11. If LC/MS is used to detect rA, under acidic conditions rA
will be detected in the protonated form and the m/e envelope will be
shifted up by one mass unit (m+1)/e: 309.09 (100.0%), 311.09 (32.2%),
310.09 (19.9%), 312.09 (6.0%), 311.10 (1.6%). Under these same
conditions, singly-labeled alprazolam will also be shifted by one mass
unit (m+1)/e: 310.09 (100.0%), 312.09 (32.2%), 311.09 (19.9%), 313.09
(6.0%), 312.10 (1.6%). These small differences in mass are easily
distinguished by mass spectrometry.

[0125]A labeled drug according to the present invention contains one or
more stable isotopes. A stable isotope includes, for example, hydrogen
2(2H), carbon 13 (13C), nitrogen 15 (15N), oxygen 17 (17O), oxygen 18
(18O), sulphur 33 (33S), sulphur (34S), sulphur 36 (36S). Stable isotopes
of other elements such as chlorine and bromine can also be used but they
are less commonly found in drugs of abuse. The compositions and methods
of the present invention provide for substitution of hydrogen (1H) with
2H, carbon (12C) with 13C, nitrogen (14N) with 15N, and oxygen (16O) with
17O or 18O, and sulphur (32S) with 33S or 34S or 36S, such that a drug is
labeled at metabolically stable sites.

[0126]A labeled drug according to the present invention can also contain
mixtures of labeled drug containing two or more different labeled
versions of the same drug in a specified ratio (e.g., a mixture of single
and double labeled drug in a ratio of 2:1).

Methods of Preventing or Stopping Drug Abuse

[0127]According to the present invention, drug abuse can be prevented by
prescribing a labeled drug to a patient; recording a patient identifier
and the labeled drug prescription in a registry accessible to providers;
testing a fluid or tissue sample from the patient for the presence of
unlabeled drug or isotopically labeled drug containing a different number
of isotopic labels than was originally prescribed. These patients would
be identified as being non-compliant with their responsibility to take
only medication prescribed by a single provider. Options such as
detoxification and drug treatment could at that point be offered.

[0128]In an aspect of the present invention, a patient can be identified
as non-compliant if the patient is tested and a mixture of labeled drug
is identified in the patient's tissues that is different than the
formulation that the patient was prescribed.

[0129]In an example according to the present invention, a doctor (i.e., a
prescriber) prescribes a labeled drug (e.g., triple-isotope labeled
diazepam) to a patient for the treatment of a medical condition (e.g.,
alcohol withdrawal). In an embodiment of the invention, a prescriber can
select a labeled drug from among a group of the same drug having
different labels (e.g., single- or double-isotope labeled diazepam);
according to this embodiment, the particular label selected is not
disclosed to the patient. Further, according to the invention, the doctor
or his staff records the labeled drug prescription in a registry by
accessing the registry using, for example, a personal computer in the
doctor's office. The data included in the recordation includes, for
example, the patient's name or unique identifier, the doctor's name, the
prescribed drug, the date of the prescription, the dosage, frequency and
duration of treatment, and the medical indication for the prescription.
In an embodiment of the invention, a pharmacist accesses the registry to
confirm recordation of the prescription prior to dispensing the drug.

[0130]In an embodiment of the present invention, the dispensing of
isotopically labeled medication, whether it be singly, doubly or multiply
labeled moieties, can be double-blind with respect to the prescribers as
well as the patients. Such double-blind dispensing can prevent
unscrupulous providers from intentionally colluding with patients to
receive medication outside of the registry system.

[0131]In an aspect of the present invention, an employer having an
employee's consent can ensure that the employee is receiving a
prescription drug as prescribed by using the registry system. By using
only isotopically labeled medication, the employer can know with
certainty that an employee is only receiving the medication in the
intended quantities. This would prevent an employee who revealed that he
is taking a medication from receiving quantities of that medication
beyond the scope of what the prescriber of the medication intends.

[0132]Further, according to the invention, insurance companies or third
party payers can be ensured that the individual who is covered by the
policy is only receiving schedule drug within the purview of the
registry. This would allow an insurer to investigate whether a schedule
drug could be exacerbating or disguising an underlying medical condition
via overuse of the prescribed agent.

[0133]Further, according to the invention, if the patient visits the same
doctor or another doctor (a provider, but not the prescriber) seeking a
prescription for a drug that they are currently being prescribed, or a
similar drug (e.g: if they are currently taking labeled oxycontin the
prescriber may want to avoid prescribing additional opiates), the doctor
(either the non-prescribing provider or the prescriber) can access the
registry and determine the patient's eligibility to receive the requested
drug. According to an embodiment of the invention, the doctor refuses to
write a prescription for the drug if a current, filled prescription for
the labeled drug is recorded in the registry. In another embodiment of
the invention, the doctor tests the patient for unlabeled and labeled
drug, and refuses to write a prescription for the patient with a recorded
prescription for labeled drug who tests positive for unlabeled drug. In a
further embodiment, a provider refuses to write a prescription for a drug
if the patient tests positive for a labeled drug (e.g., triple-isotope
labeled diazepam) different from the recorded prescribed labeled drug
(e.g., double-isotope labeled diazepam).

Methods of Monitoring Patient Compliance

[0134]According to the present invention, a patient can be monitored for
compliance with prescribed drug treatment by prescribing a labeled drug
to a patient; recording the labeled drug prescription in a registry
accessible to providers; testing a fluid or tissue sample from the
patient for the presence of labeled and unlabeled drug; and identifying
as non-compliant a patient testing negative for labeled drug. This can
prevent an individual from registering with the database, not take the
prescribed medication, and furnish the prescribed medication to a third
party.

[0135]In an example, according to the present invention, a doctor (i.e., a
prescriber) prescribes a labeled drug (e.g., triple-isotope labeled
diazepam) to a patient for the treatment of a medical condition (e.g.,
alcohol withdrawal). In an embodiment of the invention, a prescriber can
select a labeled drug from among a group of the same drug having
different labels (e.g., single- or double-isotope labeled diazepam).
According to this embodiment, the particular label selected is not
disclosed to the patient. Further, according to the invention, the doctor
or his staff records the labeled drug prescription in a registry by
accessing the registry using, for example, a personal computer in the
doctor's office. The data included in the recordation includes, for
example, the patient's name or unique identifier, the doctor's name, the
prescribed drug, the date of the prescription, the dosage, frequency, the
duration of treatment, and the medical indication for the prescription.
In an embodiment of the invention, a pharmacist accesses the registry to
confirm recordation of the prescription prior to dispensing the drug.

[0136]Further, according to the invention, the patient visits the same
doctor or another doctor (a provider, but not the prescriber). The doctor
(either the non-prescribing provider or the prescriber) accesses the
registry and tests the patient for unlabeled and labeled drug. The
patient is identified as non-compliant if the patient tests negative for
the recorded labeled drug.

Methods for Facilitating Replacement Drug Prescriptions

[0137]It is not uncommon for patients with prescribed drugs to be left
without access to their prescription drugs and in need of a replacement
prescription from a provider who was not the prescriber. For example, a
traveler who forgot to pack his prescription drug can be on a trip far
from home without a means of contacting his prescriber. In such
situations, the traveler can visit a provider who was not the prescriber
to obtain a replacement prescription. The provider may be reluctant to
write such a prescription because of the possibility that the traveler is
doctor-shopping.

[0138]The present invention provides a method for facilitating replacement
drug prescription by a provider. According to the invention, the provider
can access a registry and prescribe a replacement drug prescription to a
patient with a current labeled drug prescription recorded on the registry
in the situation where the labeled drug prescribed and recorded in the
registry is not immediately available to the patient.

Methods for Safely Tapering a Drug

[0139]The present invention provides a method for safely tapering a drug.
For example, a patient who is addicted to a drug (e.g., diazepam) sees a
provider. The provider prescribes a tapering dosage regimen of labeled
drug. For example, a patient would be dispensed a one week supply of
isotopically labeled diazepam 10 mg per day, followed by a one week
supply of isotopically labeled diazepam 7.5 mg per day, followed by a one
week supply of isotopically labeled diazepam 5.0 mg per day and then a
final one week supply of isotopically labeled diazepam 2.5 mg per day
before the patient has been safely tapered from this dependency-inducing
medication. To ensure compliance, a national database would contain a
description of the patient's tapering regimen. According to the present
invention, each dosage of drug in the regimen has a different label
(e.g., the 10 mg diazepam is triple isotope labeled and the 5 mg diazepam
is double isotope labeled). During the course of the taper regimen the
tissue or body fluid of the patient is tested for labeled and unlabeled
drug. A positive test for the labeled drug corresponding to the
appropriate drug in the taper regimen at the time of testing indicates
that the patient is properly adhering to the taper regimen (e.g., the
patient tests positive for triple isotope labeled diazepam on a day when
he should be taking triple labeled diazepam). A positive test for an
unlabeled drug or a labeled drug that should not be present in the
patient's tissue or body fluid at the time of the test indicates that the
patient is not properly adhering to the taper regimen (e.g., the patient
tests positive for double labeled diazepam on a day when he should be
taking triple labeled diazepam). A negative test for labeled drug during
the course of the taper regimen is another indication that the patient is
not adhering to the taper regimen.

[0140]Also, according to the present invention, a more gradual taper can
be achieved by mixing differently labeled drugs (e.g., a double labeled
drug with a triple labeled drug) at different ratios (e.g., 9:1, 8:2,
7:3, . . . , 1.1, . . . 9:1) while at the same time steadily decreasing
the total amount of drug in each dose. During the course of the taper
regimen the tissue or body fluid of the patient is tested for the two
labeled drugs. A positive test corresponding to the proper ratio of the
two labeled drugs in the specimen indicates that the patient is properly
adhering to the taper regimen (e.g., the patient tests positive for 80%
triple isotope labeled diazepam and 20% double isotope labeled diazepam
on a day when he should be 80% of the way through the taper regimen). A
positive test for an unlabeled drug or a labeled drug that should not be
present in the patient's tissue or body fluid at the time of the test
indicates that the patient is not properly adhering to the taper regimen
(e.g., the patient tests positive for double labeled diazepam on a day
when he should be taking triple labeled diazepam). A negative test for
labeled drug during the course of the taper regimen is another indication
that the patient is not adhering to the taper regimen.

Methods for Identifying a Patient who is Non-Compliant with a Prescription
for Medication

[0141]The present invention provides a method for identifying a
non-compliant patient who does not comply with a prescription for
medication. According to this method, for example, a patient is
prescribed a one month supply (a "period of time") of a medication. The
one month supply of medication includes, for example, a three week supply
of medication units having one isotopic label per unit and a one week
supply of medication units having two isotopic labels per unit. The
patient is instructed to self-administer the one label units for the
first three weeks of the one month (a "first predetermined interval") and
the two label units for the fourth week on the one month (a "second
predetermined interval"). At any point during the fourth week, the
patient is tested for the presence of the one label unit and the two
label unit. A negative test for the one label unit identifies a patient
who was non-compliant with the prescription during the first three weeks
of the month. A negative test for the two label unit identifies a patient
who was non-compliant during the fourth week of the month. A negative
test for both the one label unit and the two label unit identifies a
patient who was non-compliant with the prescription during the first
three weeks of the month and the fourth week of the month. According to
this method, the labeled medication administered during the first
predetermined interval must have a half-life sufficiently long to remain
at detectable levels in a patient during the second predetermined
interval.

Salts, Solvates, Prodrugs, and Stereoisomers

[0142]Typically, a pharmaceutically acceptable salt of a compound of the
present invention can be readily prepared by using a desired acid or base
as appropriate. The salt may precipitate from solution and be collected
by filtration or may be recovered by evaporation of the solvent. For
example, an aqueous solution of an acid such as hydrochloric acid may be
added to an aqueous suspension of a compound of the present invention and
the resulting mixture evaporated to dryness (lyophilized) to obtain the
acid addition salt as a solid. Alternatively, a compound of the present
invention may be dissolved in a suitable solvent, for example an alcohol
such as isopropanol, and the acid may be added in the same solvent or
another suitable solvent. The resulting acid addition salt may then be
precipitated directly, or by addition of a less polar solvent such as
diisopropyl ether or hexane, and isolated by filtration.

[0143]The acid addition salts of a compound of the present invention can
be prepared by contacting the free base form with a sufficient amount of
the desired acid to produce the salt in the conventional manner. The free
base form may be regenerated by contacting the salt form with a base and
isolating the free base in the conventional manner. The free base forms
differ from their respective salt forms somewhat in certain physical
properties such as solubility in polar solvents, but otherwise the salts
are equivalent to their respective free base for purposes of the present
invention.

[0145]Those skilled in the art of organic chemistry will appreciate that
many organic compounds can form complexes with solvents in which they are
reacted or from which they are precipitated or crystallized. These
complexes are known as "solvates". For example, a complex with water is
known as a "hydrate". Solvates of the compound of the invention are
within the scope of the invention. The salts of a compound of the present
invention can form solvates (e.g. hydrates) and the invention also
includes all such solvates.

[0146]The present invention also encompasses prodrugs of the
aforementioned compounds of the present invention, i.e., compounds which
release an active parent drug according to the aforementioned compounds
in vivo when administered to a mammalian subject. Prodrugs are generally
prepared by modifying functional groups in a way such that the
modification is cleaved, either by routine manipulation or in vivo,
yielding the parent compound. Prodrugs include, for example, compounds of
this invention wherein hydroxy, amine or sulfhydryl groups are bonded to
any group that, when administered to a patient, cleaves to form the
hydroxy, amine or sulflhydryl groups. Thus, representative examples of
prodrugs include (but are not limited to) acetate, formate and benzoate
derivatives of alcohol, sulflhydryl and amine functional groups of a
compound of the present invention. Further, in the case of a carboxylic
acid (--COOH), esters may be employed, such as methyl esters, ethyl
esters, and the like. Esters may be active in their own right and/or be
hydrolysable under in vivo conditions in the human body. Suitable
pharmaceutically acceptable in vivo hydrolysable ester groups include
those which break down readily in the human body to leave the parent acid
or its salt.

[0147]A compound of the present invention can exist in numerous forms of
structural isomers that may be formed as a result of tautomerism, and may
exist in different ratios at equilibrium. Due to dynamic equilibrium such
isomers (tautomers) are rapidly interconvertible from one isomeric form
to another. The most common isomerism is keto-enol tautomerism, but
equilibrium between open chain and cyclic forms are also known. It is to
be understood that whenever in the present invention we refer to
aforementioned compounds of the present invention, we mean to include
tautomeric forms thereof, keto-enol tautomeric, open chain-cyclic,
isolated as separate isomers or existing in any other mixture of
different ratios at equilibrium. The isomeric forms predominant for a
particular compound of the present invention are dependent on the nature
of the substituent, whether the compound exists in the free form or in
the form of any of its salts, type of the salt, solvent in which the
compound is dissolved, as well as pH value of the solution.

[0148]Compounds of the present invention may further exist as different
geometric isomers or different stereoisomers. Isomers that differ only
with regard to the arrangement of the atoms in the space around the
asymmetric (stereogenic, chiral) center are called "stereoisomers".
Stereoisomers that are not mirror images of each other are called
diastereomers, while stereoisomers that have a mirror-image relationship,
i.e. that are mirror images of each other, are called enantiomers. Each
stereoisomer may be characterized by determining the absolute
configuration of the stereogenic center by the use of Cahn-Ingold-Prelog
priority rules and hence characterized as the R- or S-isomer. Another way
of identification of stereoisomers is the measurement of the rotation of
the plane of polarized light that passes through the molecule, and
designating chiral molecules to be right-rotating (+) or left-rotating
(-) isomers. Chiral molecules may exist in a form of single enantiomer or
in a mixture of enantiomers. A mixture consisting of equal parts (+) and
(-) enantiomers of a chiral substance is called racemic mixture. The
present invention relates to each stereoisomer that may be shown by the
aforementioned compounds of the present invention either isolated as
separate enantiomers, diastereomers or existing in racemic or any other
mixture thereof.

[0149]Methods for determination of stereochemical configuration,
resolution and separation of stereoisomers are well known from the
literature. The enantiomers may be resolved by methods known to those
skilled in the art, for example by formation of diastereomeric salts
which may be separated, for example, by crystallization; formation of
diastereomeric derivatives or complexes which may be separated, for
example, by crystallization, gas-liquid or liquid chromatography;
selective reaction of one enantiomer with an enantiomer-specific reagent,
for example enzymatic esterification; or gas-liquid or liquid
chromatography in a chiral environment, for example on a chiral support
for example silica with a bound chiral ligand or in the presence of a
chiral solvent. The diastereomeric pairs may be separated by methods
known to those skilled in the art, for example chromatography or
crystallization and the individual enantiomers within each pair may be
separated as described above.

[0150]The present invention also encompasses stereoisomers of the syn-anti
type, and mixtures thereof encountered when an oxime or similar group is
present. The group of highest Cahn-Ingold-Prelog priority attached to one
of the terminal doubly bonded atoms of the oxime, is compared with
hydroxy group of the oxime. The stereoisomer is designated as Z
(zusammen=together) or Syn if the oxime hydroxyl lies on the same side of
a reference plane passing through the C═N double bond as the group of
highest priority; the other stereoisomer is designated as E
(entgegen=opposite) or Anti.

[0151]Compounds of the present invention may be in crystalline or
amorphous form. Furthermore, some of the crystalline forms of the
aforementioned compounds of the present invention may exist as
polymorphs, which are included in the present invention.

Pharmaceutical Compositions

[0152]While it is possible that, for use in therapy, a compound of the
invention may be administered as the raw chemical, it is preferable to
present the active ingredient in a pharmaceutical formulation, e.g., when
the agent is in admixture with a suitable pharmaceutical excipient,
diluent or carrier selected with regard to the intended route of
administration and standard pharmaceutical practice.

[0153]Accordingly, in one aspect, the present invention provides a
pharmaceutical composition or formulation comprising at least one
compound of the invention or a pharmaceutically acceptable derivative
thereof in association with a pharmaceutically acceptable excipient,
diluent and/or carrier. The excipient, diluent and/or carrier must be
"acceptable" in the sense of being compatible with the other ingredients
in the formulation and not deleterious to the recipient thereof.

[0154]The term "pharmaceutically acceptable", as used in connection with
compositions of the invention, refers to molecular entities and other
ingredients of such compositions that are physiologically tolerable and
do not typically produce untoward reactions when administered to a mammal
(e.g., human). Preferably, as used herein, the term "pharmaceutically
acceptable" means approved by a regulatory agency of the Federal or a
state government or listed in the U.S. Pharmacopeia or other generally
recognized pharmacopeia for use in mammals, and more particularly in
humans.

[0155]The term "carrier" applied to pharmaceutical compositions of the
invention refers to a diluent, excipient, or vehicle with which an active
compound is administered. Such pharmaceutical carriers can be sterile
liquids, such as water, saline solutions, aqueous dextrose solutions,
aqueous glycerol solutions, and oils, including those of petroleum,
animal, vegetable or synthetic origin, such as peanut oil, soybean oil,
mineral oil, sesame oil and the like. However, since benzodiazulene salt
are highly soluble, aqueous solutions are preferred. Suitable
pharmaceutical carriers are described in "Remington's Pharmaceutical
Sciences" by E. W. Martin, 18th Edition. Particularly preferred for the
present invention are carriers suitable for immediate-release, i.e.,
release of most or all of the active ingredient over a short period of
time, such as 60 minutes or less, and make rapid absorption of the drug
possible.

[0156]The term "pharmaceutically acceptable derivative" as used herein
means any pharmaceutically acceptable salt, solvate or prodrug, e.g.
ester, of a compound of the invention, which upon administration to the
recipient is capable of providing (directly or indirectly) a compound of
the invention, or an active metabolite or residue thereof. Such
derivatives are recognizable to those skilled in the art, without undue
experimentation. Nevertheless, reference is made to the teaching of
Burger's Medicinal Chemistry and Drug Discovery, 5th Edition, Vol 1:
Principles and Practice, which is incorporated herein by reference to the
extent of teaching such derivatives. Preferred pharmaceutically
acceptable derivatives are salts, solvates, esters, carbamates and
phosphate esters. Particularly preferred pharmaceutically acceptable
derivatives are salts, solvates and esters. Most preferred
pharmaceutically acceptable derivatives are salts and esters.

[0157]The compounds of the invention may be formulated for administration
in any convenient way for use in human or veterinary medicine and the
invention therefore includes within its scope pharmaceutical compositions
comprising a compound of the invention adapted for use in human or
veterinary medicine. Such compositions may be presented for use in a
conventional manner with the aid of one or more suitable excipients,
diluents and/or carriers. Acceptable excipients, diluents and carriers
for therapeutic use are well known in the pharmaceutical art, and are
described, for example, in Remington's Pharmaceutical Sciences, Mack
Publishing Co. (A. R. Gennaro edit. 1985). The choice of pharmaceutical
excipient, diluent and/or carrier can be selected with regard to the
intended route of administration and standard pharmaceutical practice.
The pharmaceutical compositions may comprise as--or in addition to--the
excipient, diluent and/or carrier any suitable binder(s), lubricant(s),
suspending agent(s), coating agent(s), solubilizing agent(s).

[0158]Preservatives, stabilizers, dyes and even flavoring agents may be
provided in the pharmaceutical composition. Examples of preservatives
include sodium benzoate, ascorbic acid and esters of p-hydroxybenzoic
acid. Antioxidants and suspending agents may be also used.

For some embodiments, the agents of the present invention may also be used
in combination with a cyclodextrin. Cyclodextrins are known to form
inclusion and non-inclusion complexes with drug molecules. Formation of a
drug-cyclodextrin complex may modify the solubility, dissolution rate,
bioavailability and/or stability property of a drug molecule.
Drug-cyclodextrin complexes are generally useful for most dosage forms
and administration routes. As an alternative to direct complexation with
the drug the cyclodextrin may be used as an auxiliary additive, e.g. as a
carrier, diluent or solubilizer. Alpha-, beta- and gamma-cyclodextrins
are most commonly used and suitable examples are described in WO
91/11172, WO 94/02518 and WO 98/55148.

[0159]The compounds of the invention may be milled using known milling
procedures such as wet milling to obtain a particle size appropriate for
tablet formation and for other formulation types. Finely divided
(nanoparticulate) preparations of the compounds of the invention may be
prepared by processes known in the art, for example see International
Patent Application No. WO 02/00196 (SmithKline Beecham).

[0161]Additionally, lubricating agents such as magnesium stearate, stearic
acid, glyceryl behenate and talc may be included.

[0162]Solid compositions of a similar type may also be employed as fillers
in gelatin capsules. Preferred excipients in this regard include lactose,
starch, a cellulose, milk sugar or high molecular weight polyethylene
glycols. For aqueous suspensions and/or elixirs, the agent may be
combined with various sweetening or flavoring agents, coloring matter or
dyes, with emulsifying and/or suspending agents and with diluents such as
water, ethanol, propylene glycol and glycerin, and combinations thereof.

[0163]The compounds of the invention may also be used in combination with
other therapeutic agents. The invention thus provides, in a further
aspect, a combination comprising a compound of the invention or a
pharmaceutically acceptable derivative thereof together with a further
therapeutic agent. The combinations may conveniently be presented for use
in the form of a pharmaceutical formulation and thus pharmaceutical
formulations comprising a combination as defined above together with a
pharmaceutically acceptable carrier or excipient comprise a further
aspect of the invention. The individual components of such combinations
may be administered either sequentially or simultaneously in separate or
combined pharmaceutical formulations by any convenient route.

[0164]When administration is sequential, either the compound of the
invention or the second therapeutic agent may be administered first. When
administration is simultaneous, the combination may be administered
either in the same or different pharmaceutical composition.

[0165]When combined in the same formulation it will be appreciated that
the two compounds must be stable and compatible with each other and the
other components of formulation. When formulated separately they may be
provided in any convenient formulation, conveniently in such manner as
are known for such compounds in the art.

[0166]The compositions may contain from 0.01-99% of the active material.

[0167]The preparation of pharmaceutical formulations may include blending,
granulating, tabletting and dissolving the ingredients. Pharmaceutically
acceptable carriers (binders and fillers) may be solid or liquid. Solid
carriers may be lactose, sucrose, talcum, gelatine, agar, pectin,
magnesium stearate, fatty acids etc. Liquid carriers may be syrups, oils
such as olive oil, sunflower oil or soy bean oil, water etc. Similarly,
the pharmaceutically acceptable Formulations may also contain a component
for a sustained release of the active component such as e.g. glyceryl
monostearate or glyceryl distearate.

Dosages

[0168]The dosage of a labeled drug according to the present invention is
the same as the dosage of the corresponding unlabeled drug, e.g., labeled
diazepam according to the present invention is dosed in the same amount
and frequency as unlabeled diazepam.

[0169]Typically, a physician will determine the actual dosage which will
be most suitable for an individual subject. The specific dose level and
frequency of dosage for any particular individual may be varied and will
depend upon a variety of factors including the activity of the specific
compound employed, the metabolic stability and length of action of that
compound, the age, body weight, general health, sex, diet, mode and time
of administration, rate of excretion, drug combination, the severity of
the particular condition, and the individual undergoing therapy. The
daily dosage level of the agent may be in single or divided doses.

Methods of Synthesizing a Labeled Drug

[0170]It will be appreciated by those skilled in the art that it may be
desirable to use protected derivatives of intermediates used in the
preparation of the compounds of Formulae I-IV. Protection and
deprotection of functional groups may be performed by methods known in
the art. Hydroxyl or amino groups may be protected with any hydroxyl or
amino protecting group, for example, as described in Green T. W.; Wuts P.
G. M. Protective Groups in Organic Synthesis: John Wiley and Sons, New
York, 1999. The amino protecting groups may be removed by conventional
techniques. For example, acyl groups, such as alkanoyl, alkoxycarbonyl
and aryloyl groups, may be removed by solvolysis, e.g., by hydrolysis
under acidic or basic conditions. Arylmethoxycarbonyl groups (e.g.,
benzyloxycarbonyl) may be cleaved by hydrogenolysis in the presence of a
catalyst such as palladium-on-charcoal.

[0171]The synthesis of the target compound is completed by removing any
protecting groups, which are present in the penultimate intermediate
using standard techniques, which are well known to those skilled in the
art. The deprotected final product is then purified, as necessary, using
standard techniques such as silica gel chromatography, HPLC on silica
gel, and the like or by recrystallization.

Synthesis of Labeled Benzodiazepines

[0172]Compounds of Formula I and pharmaceutically acceptable derivatives
thereof may be prepared by the general methods outlined hereinafter, said
methods constituting a further aspect of the invention. In the following
description, the groups R1 to R4, X1, X2 have the
meaning defined for the compounds of Formula I unless otherwise stated.

[0173]A further object of the present invention relates to the preparation
of compounds of Formula I according to processes comprising:

(a) For compounds of Formula I, wherein there is a C--N single bond
between nitrogen 1 and carbon 2, X1 is oxygen and there is a C═O
double bond between X1 and carbon 2, and X2 is hydrogen and
R3 is hydrogen and R4 is no substituent:condensing of a
compound of Formula B1:

##STR00014##

wherein

[0174]the compound B1 can contain from zero to at least one isotopic
labels;

[0175]R1 is selected from chlorine, fluorine or nitro; and

[0176]R2 is selected from hydrogen, fluorine, or chlorine,

with an isotopically labeled compound B2

##STR00015##

wherein

[0177]at least one atom labeled with "*" is a stable isotope such as
13C for C, 15N for N, 18O for O and 2H for H;

[0178]Y is a leaving group such as chloro, fluoro, or substituted phenyl
alkoxide;

[0179]P1 is an amine protecting group,

then removing the protecting group P1 to produce a compound of
formula B3:

##STR00016##

wherein

[0180]compound B3 contains at least two isotopic labels, and

then intramolecularly dehydrating B3 (e.g. refluxing benzene with a
Dean-Stark trap) to form a compound of formula B4:

##STR00017##

whereincompound B4 contains at least two isotopic labels.(b) For compounds
of Formula I, wherein there is a C--N single bond between nitrogen 1 and
carbon 2, X1 is oxygen and there is a C═O double bond between
X1 and carbon 2, and R3 is hydrogen, R4 is no substituent,
and X2 is methyl (--CH3),
--CH2CH2N(CH2CH3)2, trifluoroethyl
(--CH2CF3), or methylenecyclopropyl

##STR00018##

comprising treating an isotopically labeled compound B4 with a strong base
(e.g. sodium hydride), and then treating the compound with an alkyl
halide such as CH3I,

I--CH2CH2N(CH2CH3)2, I--CH2CF3, or

##STR00019##

[0181]to produce a compound of formula B5:

##STR00020##

whereincompound B5 contains at least two isotopic labels.(c) For compounds
of Formula I, wherein there is a C--N single bond between nitrogen 1 and
carbon 2, X2 is hydrogen or methyl, X1 is oxygen and there is a
C--O double bond between X1 and carbon 2, and R3 is hydroxy,
and R4 is no substituent, comprisingreacting a compound of Formula
B5:

##STR00021##

whereincompound B5 contains at least two isotopic labels with an electron
poor peroxyacid,then treating the resulting product with a compound of
formula B6,

##STR00022##

wherein

[0182]R1 and R2 are independently selected from C1-C6
alkyl,

and then saponifying (i.e., hydrolysis) of the ester intermediate.(d) For
compounds of Formula I, wherein there is a C--N single bond between
nitrogen 1 and carbon 2, X1 and X2 together represent the
bridge

##STR00023##

and R3 is hydrogen and R4 is no substituent, comprising treating
a compound of Formula B7,

##STR00024##

whereincompound B7 contains at least two isotopic labels,with a base, then
reacting the compound with diethylchloropliosphate and then reacting the
a compound with a compound of formula B8

##STR00025##

See Walser et. al J. Med. Chem. (1991) 34, 1209-1221 for methods of making
triazole rings.e) For compounds of Formula I, wherein there is a C--N
double bond between nitrogen 1 and carbon 2, X2 is no substituent,
X1 is methylamino and there is a C--N single bond between X1
and carbon 2, R3 is hydrogen, and R4 is oxygen, a compound of
Formula B9

##STR00026##

is treated with mCPBA to form a compound of formula B10

##STR00027##

which is reacted with methylamine using titanium tetrachloride as a
catalyst.

Preparation Methods for Labeled Benzodiazepines:

[0183]The compounds of Formula I can be prepared by the methods disclosed
above using standard protocols known in the art of organic chemistry.

a) Respecting the compounds of Formula I wherein synthesis occurs via the
compounds of Formula B3, reaction can occur in the presence of base and
under the appropriate conditions for dehydration and imine condensation.
Appropriate bases are, for example, pyridine, NEt3, and Hunig's base
and the reaction may be carried out in the presence of Mg2SO4,
molecular sieves, or under Dean-Stark conditions for removal of water
from the system. The condensation to form the diazepine ring structure
can take place in neat base, or in the presence of a solvent such as
toluene and is normally reacted under refluxing conditions. The reaction
is stirred in air or under a nitrogen atmosphere until the water has been
substantially removed from the system. Upon completion, the solvents can
be removed iii vacuo and the crude product purified by recrystallization
or by chromatography (e.g., silica gel or preparative HPLC). Optionally,
the base can be removed by extraction with aqueous acid (e.g., ammonium
chloride).b) Respecting the compounds of Formula I wherein synthesis
occurs between the compounds of Formula B5 and B6, reaction can occur in
a suitable organic solvent (e.g.: CH2Cl2, CHCl3,
dimethylformamide etc.) or by the addition of a compound of Formula B5 to
the neat anhydride. Generally, the reaction is heated to an appropriate
temperature (e.g., 50-80° C.) until substantial conversion has
been reached. Solvent and excess anhydride can then be removed in vacuo
or the reaction system can be extracted with aqueous acid to remove the
anhydride. The crude product purified by recrystallization (e.g., in
ethanol) or by chromatography.c) Respecting the compounds of Formula I
wherein synthesis occurs between the compounds of Formula B7 and B8,
reaction can occur by treating B7 (0.04 mol) in 350 mL of THF with
potassium tert-butoxide (0.044 mol) and stirring under N2 for 30 min at
-10 to -5 degrees celsius. Diethyl chlorophosphate (6.6 mL) is then added
and the mixture is stirred at this temperature for another 30 min.
Following the addition of acetic hydrazide (3.4 g), stirring without
cooling is continued for 1 h and 1-butanol (150 mL) is added. The THF and
part of the 1-butanol is distilled out of the reaction mixture over a
period of 45 min. The residue is partitioned between toluene and water.
The organic phase is washed with brine, dried, and evaporated.d)
Respecting the compounds of Formula I wherein synthesis occurs from a
compound of Formula B10, reaction can occur by treating BIO with
methylamine in tetrahydrofuran at ice-bath temperature with a
tetrahydrofuran-titanium tetrachloride complex. For reference see: Fryer
and co-workers, J. Org. Chem. (1969) 34, 1143-1145.e) The compounds of
Formula B5 can be prepared by a reaction of the compounds of Formula B11
wherein R5 and X2 are selected from hydrogen or methyl,

##STR00028##

wherein

[0184]the compound B1 can contain from zero to at least one isotopic
labels;

with an isotopically labeled compound B2

##STR00029##

wherein [0185]at least one atom labeled with "*" is a stable isotope
such as 13C for C, 15N for N, 18O for O and 2H for H;
and [0186]P1 is preferably tert-butoxycarbonyl (Boc) or benzyloxy
carbonyl (Cbz).

[0187]The coupling of B1 and B2 can be carried out with the carboxylic
acid functionality in place or with suitably activated derivatives of
carboxylic acid, followed where necessary by subsequent removal of the
amino protecting group. Suitably activated derivatives of the carboxylic
acid include the corresponding acid halide (preferably the acid
chloride), mixed anhydride or an activated ester (e.g., a thiol ester).
The reaction is preferably carried out in a suitable aprotic solvent such
as a halohydrocarbon (e.g. dichloromethane) or N,N-dimethylformamide and
optionally in the presence of a tertiary base such as
dimethylaminopyridine (DMAP) or triethylamine, or in the presence of
inorganic base (e.g. sodium hydroxide) and at a temperature within the
range of 0 to 120° C. The compounds of formulae B1 and B2 may also
be reacted directly in the presence of a carbodiimide such as
dicyclohexylcarbodiimide (DCC) or EDC. The deprotection of the amino
protecting group, if appropriate, is carried out using techniques known
in the art, for example; the Cbz group can be removed with hydrogenation
in the presence of a palladium catalyst on carbon, or in the presence of
an aqueous or organic acid.

f) The compounds of formula B6 are either commercially available, or can
prepared by condensation of the appropriate carboxylic acids under
dehydrating conditions.g) The compounds of Formula B7 are prepared from
the compounds of Formula B3 under the conditions set forth for the
synthesis of the Formula I compounds wherein the Formula B3 compounds are
employed as an intermediate.h) Besides the above-mentioned reactions, the
compounds of Formula I may be prepared by transforming other compounds of
Formula I and it is to be understood that the present invention also
comprises such compounds and processes. An example is set forth in above
preparation method (i). An additional example could be the conversion of
a Formula I compound wherein X2 is hydrogen to a formula I compounds
wherein X2 is methyl. The reaction can be carried out in the
presence of a base appropriate for nitrogen deprotonation (e.g., NaH,
LDA, K2CO3, NaOtBu) and subsequent quenching of the nitrogen
anion with a methyl electrophile (preferably MeI).

Synthesis of Labeled Amphetamines

[0188]Compounds of Formula II and pharmaceutically acceptable derivatives
thereof may be prepared by the general methods outlined hereinafter, said
methods constituting a further aspect of the invention. In the following
description, the group R5 has the meaning defined for the compounds
of Formula II unless otherwise stated.

[0189]A further object of the present invention relates to the preparation
of compounds of Formula II according to processes comprising:

(a) for compounds of Formula II, wherein R5 has the meaning of
hydrogen or methyl, reducing a compound of Formula A1

##STR00030##

whereincompound A1 contains at least two isotopic labels; andX3 is
hydroxy or oxo.(b) Additionally, for compounds of Formula II, wherein
R5 has the meaning of hydrogen, reducing a compound of Formula A2:

##STR00031##

wherein compound A2 contains at least two isotopic labels; andthe
nitroalkene can be present in the E or Z form or as a mixture thereof.(c)
For compounds of Formula II, wherein R5 has the meaning of hydrogen
or methyl, reducing a compound of Formula A3

##STR00032##

whereincompound A3 contains no or at least two isotopic labels;in the
presence of NHR6, wherein R6 is selected from hydrogen or
methyl(d) For compounds of Formula II, wherein R1 has the meaning of
methyl, reducing a compound of formula A4

##STR00033##

whereincompound A4 contains no or at least two isotopic labels.(e) For
compounds of Formula II, wherein R5 has the meaning of hydrogen,
hydrolysis of sulfinate A5

##STR00034##

whereincompound A5 contains at least two isotopic labels.

Preparation Methods for Labeled Amphetamines:

[0190](a) Respecting the compounds of Formula II wherein synthesis occurs
via the compounds of Formula A1, reaction can occur in the presence of a
reducing agent. Appropriate reducing agents are those capable of reducing
a benzylic alcohol or ketone to a benzylic methylene (e.g., LiAlH4).
The reaction is carried out in an appropriate organic solvent, for
example, THF, diethylether, or hexane, and at a temperature from
0° C. to 70° C. The reaction is stirred in air or under a
nitrogen atmosphere until the benzylic oxygen has been substantially
reduced, and upon completion excess reducing agent can be quenched by the
addition of base (e.g., NaOH). Aluminium or boron salts can the be
removed by filtration or aqueous extraction and the solvent can be
removed in vacuo. The crude product can then purified by
recrystallization or by distillation.(a) Respecting the compounds of
Formula II wherein synthesis occurs via the compounds of Formula A2,
reaction can occur in the presence of a reducing agent. Appropriate
reducing agents are those capable of reducing a nitrostyrene to the
corresponding phenethylamine (e.g., LiAlH4). The reaction is carried
out in an appropriate organic solvent, for example, THF, diethylether, or
hexane, and at a temperature from 0° C. to 70° C. The
reaction is stirred in air or under a nitrogen atmosphere until the
benzylic oxygen has been substantially reduced, and upon completion
excess reducing agent can be quenched by the addition of base (e.g.,
NaOH). Aluminium or boron salts can the be removed by filtration or
aqueous extraction and the solvent can be removed in vacuo. The crude
product can then be purified by distillation.c) Respecting the compounds
of Formula II wherein synthesis occurs via the compounds of Formula A3,
reaction can occur in the presence of the appropriate amine base or salt,
and with the appropriate reducing agent for a reductive amination (e.g.,
NaBH3CN, NaBH(OAc)3. For example, to a solution of a compound
of formula A3 in THF, a solution of methyl amine in THF and solid
NaBH(OAc)3 are added. The reaction is stirred at an appropriate
temperature (e.g., 25° C.) until the reduction is substantially
complete and the reducing agent is then quenched with the addition of
aqueous base. Reaction byproducts are then removed by extraction and the
product can be purified by distillation.d) Respecting the compounds of
Formula II wherein synthesis occurs via the compounds of Formula A4,
reaction can occur in the presence of a reducing agent. Appropriate
reducing agents are those capable of reducing an N-formyl group to an
N-methyl group (e.g., LiAlH4). The reaction is carried out in an
appropriate organic solvent, for example, THF, diethylether, or hexane,
and at a temperature from 0° C. to 70° C. The reaction is
stirred in air or under a nitrogen atmosphere until the benzylic oxygen
has been substantially reduced, and upon completion excess reducing agent
can be quenched by the addition of base (e.g., NaOH). Aluminum or boron
salts can the be removed by filtration or aqueous extraction and the
solvent can be removed in vacuo. The crude product can then be purified
by distillation.e) The compounds of Formula A1 can be prepared, for
example, by a reacting phenyllithium (available commercially or prepared
by the addition of an alkyllithium reagent to bromobenzene at low
temperature (e.g., -78° C.) with a Weinreb amide of Formula A6.

##STR00035##

wherein P1 is hydrogen or a protecting group for an amine (e.g., Boc
or Cbz).

[0191]The phenyllithium reagent is slowly added to the Weinreb amide at
low temperature and the reaction is then allowed to warm to room
temperature. Upon substantial conversion to product, the reaction is
quenched by the addition of water or aqueous acid and the product
purified by recrystallization of chromatography.

f) The compound of formula A2 can be prepared by the adding nitroethane to
the appropriately isotopically labeled benzaldehyde (i.e., a Henry
reaction). The reaction is carried out in an organic solvent, in acetic
acid, or in an organic solvent/aqueous base biphasic mixture and in the
presence of a base capable of deprotonating nitroethane (e.g., amine
bases, NaOH). Additionally the reaction is performed under appropriate
conditions such that the intermediate nitroaldol product is dehydrated to
the nitrostyrene. The condensation can take place, for example, by
heating the reaction mixture in acetic acid. The crude product can then
be purified by recrystallization or chromatography.g) Besides the
above-mentioned reactions, the compounds of Formula II may be prepared by
transforming other compounds of Formula II and it is to be understood
that the present invention also comprises such compounds and processes.
An example is set forth in above preparation method (d) wherein an
isotopically labeled amphetamine can be converted to the corresponding
methamphetamine be conversion to N-formyl amphetamine followed by
reduction. N-formyl amphetamine can be prepared by the methods known in
the art, for example, by reaction with formic acid under conditions
appropriate for condensation (azetropic removal of water) or by reaction
with formic acid in the presence of a peptide coupling reaction such as a
carbodiimide (e.g., DCC or EDC). Additionally, the compound of Formula II
wherein R5 is methyl can be prepared from the compound of Formula II
wherein R5 is hydrogen by treatment of the latter with
paraformaldehyde (or another formaldehyde equivalent know in the art) and
reduction of the intermediate imine with a suitable reducing agent (e.g.,
LiAlH4).

Synthesis of Labeled Methylphenidate

[0192]For a preparative method for the synthesis of labeled
methylphenidate, refer to FIG. 5 and Example 5.

Synthesis of Labeled Fentanyl

[0193]For the synthesis of labeled fentanyl, coupling of a compound of
Formula F1,

##STR00036##

wherein

[0194]F1 contains one or more 1H, 13C, 18O labels; and

[0195]L is hydroxy or an appropriate leaving group (e.g., chloride,
thioester) with a compound of Formula F2,

[0197]The present invention is also described by means of the following
examples. However, the use of these or other examples anywhere in the
specification is illustrative only and in no way limits the scope and
meaning of the invention or of any exemplified term. Likewise, the
invention is not limited to any particular preferred embodiments
described herein. Indeed, many modifications and variations of the
invention may be apparent to those skilled in the art upon reading this
specification and can be made without departing from its spirit and
scope. The invention is therefore to be limited only by the terms of the
appended claims along with the full scope of equivalents to which the
claims are entitled.

Example 1

Synthesis of (1,2-13C2, 98%) Lorazepam

[0198]The synthesis of double isotope labeled lorazepam was carried out
using a modification of the protocol set forth in Koves, G. J. (Journal
of Radiolabeled Compounds and Radiopharmaceuticals (1991) 29(1) 15-22)
and described in detail in FIG. 1 and the following description.

Intermediate 1 (I-1): N-Cbz-(1,2-13C2, 98%)-glycine

[0199]To a 500 mL three neck flask fitted with a reflux condenser, rubber
septum, nitrogen adapter and magnetic stir bar will be added
(U-13C2, 98%) glycine (SM-1) (8.9 g, 114.4 mmol). The solid
will be suspended in 245 mL of CH2Cl2. Diisopropylethylamine
(65.6 mL, 377.5 mmol) will be added with stirring. Chlorotrimethylsilane
(65.6 mL, 514.8 mmol) will then be added slowly, and the solution
refluxed for 1.5 hours. The flask will be transferred to an ice bath, and
benzyl chloroformate (Cbz-Cl, 15.6 mL, 108.7 mmol) is added in one
portion via syringe. The stirred solution will be allowed to warm to room
temperature overnight. The reaction mixture will then be concentrated and
added to 1 L of 2.5% aqueous NaHCO3 and transferred to a separatory
funnel. The solution will be washed with ether (3×200 mL). The
ether washes will then be combined and back extracted with water
(2×200 mL). The aqueous layers will be combined and acidified to pH
2 with 2M aqueous HCl. This solution will be extracted with EtOAc
(4×250 mL). The EtOAc layers will be washed with brine (3×250
mL), dried over Na2SO4, and filtered. The solvent will be
evaporated in vacuo, yielding the desired product I-1 (expected yield
21.7 g, 102.6 mmol, 95%)

Intermediate 2 (I-2): N-Cbz-(1,2-13C2, 98%)-glycine acid
chloride

[0200]To 100 mL of toluene will be added 5.6 g (27 mmol) triply labeled
carbobenzyloxyglycine (I-1) to form a suspension. To this suspension will
be added dimethylformamide (1 mL) and then oxalyl chloride (2.7 mL, 30
mmol) drop wise at room temperature. After ten minutes the solution
should become clear. At this point the toluene, excess oxalyl chloride
and HCl will be removed under reduced pressure. The residual oil will be
dissolved in dry toluene and the toluene will be removed under reduced
pressure yielding the desired product I-2 (expected yield 6.2 g, 27 mmol,
quantitative). The acid chloride I-2 will be used without further
purification.

[0201]To 8 mL of dry ether will be added 1.4 g (6.07 mmol) of the triply
labeled Cbz-glycine acid chloride (I-2). To this solution will be added
dropwise 1.65 g (6.2 mmol) of
(2-amino-5-chlorophenyl)(2-chlorophenyl)methanone (SM-2) dissolved in 30
mL of dry ether over 40 min. A crystal slurry should form and it will be
stirred for another two hours. The pH will be adjusted to 11 by slow
addition of 5N NaOH and the solution will be stirred for another two
hours. The ether layer will be separated and washed with water several
times followed by several washes with 1M HCl. The organic extracts will
be dried over anhydrous Na2SO4. The filtered solution will be
evaporated in vacuo. The residue will be crystallized in 100 mL ethanol
to produce I-3 (expected yield 2.4 g, 5.3 mmol, 85%).

[0202]A solution of 1.5 g (3.26 mmol) of I-3 and 8 mL of 30% HBr in acetic
acid will be stirred for 1 hour at room temperature. After 1 hour 100 mL
of dry ether will be added and the mixture will be stirred for five
minutes. The ether solution will be decanted and the precipitate will be
washed with 50 mL of dry ether. The solid will be suspended in 25 mL of
ether, chilled in an ice bath and 8 mL of 10% NaOH will be added. This
mixture will be stirred and the ether will then be separated, washed with
water and evaporated under reduced pressure to yield I-4 (expected yield
1.06 g, 3.26 mmol, quantitative yield). The product I-4 will be used
without further purification.

[0204]A solution of 1 g (3.26 mmol) of I-5 in 50 mL of CH2Cl2
will be added dropwise to a stirred solution of 0.83 g (4.8 mmol)
m-chloroperoxybenzoic acid (previously washed with a pH 7.4 buffer
solution and dried in vacuo) in 10 mL of CH2Cl2 at 20 to
25° C. The solution will be stirred for 10 hours at room
temperature and then another 0.83 g (4.8 mmol) m-chloroperoxybenzoic will
be added. After another 10 hours of constant stirring the reaction
mixture will be brought to pH 8.0 with 25% ammonium hydroxide and washed
thoroughly with water. The solid white precipitate will be filtered and
dried in vacuo. The combined solids will be crystallized from 7 mL of
ethanol to produce the product I-6 (expected yield 0.8 g, 2.47 mmol,
75%).

[0205]A suspension of 1.0 g (3.1 mmol) of I-6 in 10 mL of acetic anhydride
will be stirred and heated on a water bath for three hours at
60-70° C. Once the solution clears it will be evaporated in vacuo
and the residue will be dissolved in 5 mL of ethanol and crystallized to
produce the product 1-7 (expected yield 1.0 g, 2.75 mmol, 88%).

(1,2-13C2, 98%)-Lorazepam

[0206]One gram of I-7 (2.75 mmol) will be dissolved in 10 mL of methanol
and then 6 mL of 4N NaOH will be added. After 30 min, a solid precipitate
is expected that will dissolve on the addition of 50 mL water. The
solution will be acidified with acetic acid and extracted with
CH2C12. After separation, the CH2Cl2 will be washed three
times with 20 mL of water, dried on Na2SO4 and evaporated in
vacuo. The solid will be purified on preparative HPLC (mobile phase:
MeOH:H2O, 30:70, flow rate: 10 mL/min). Fractions containing 1 will
be combined, evaporated and crystallized in 2 mL ethanol to produce pure
1 (0.47 g, 1.46 mmol, 53%).

Example 2

Synthesis of (1,2-13C2-3-15N, 98%) Lorazepam

[0207]The synthesis of triple isotope labeled lorazepam was carried out
using a modification of the protocol set forth in Koves, G. J. (Journal
of Radiolabeled Compounds and Radiopharmaceuticals (1991) 29(1) 15-22)
and is described in FIG. 2. The synthesis is a modification of the
protocol set forth in Example 1 with the only difference in the synthetic
details being the use of (U-3C2, 98%, 15N, 98%) glycine (SM-3)
as the amino acid precursor.

Example 3

Synthesis of (1,2-13C2-3-15N, 98%) Oxazepam

[0208]The synthesis of triple isotope labeled oxazepam was carried out
using a modification of the protocol set forth in Koves, G. J. (Journal
of Radiolabeled Compounds and Radiopharmaceuticals (1991) 29(1) 15-22)
and is described in FIG. 3. The synthesis is a modification of the
protocol set forth in Example 1 with the only difference in the synthetic
details being the use of (U-13C2, 98%, 15N, 98%) glycine
(SM-3) as the amino acid precursor and (2-amino-5-chloro)-benzophenone as
the benzophenone precursor (SM-5).

Example 4

Synthesis of (1,2-13C2-3-15N, 98%) Clonazepam

[0209]The synthesis of triple isotope labeled clonazepam was carried out
using a modification of the protocol set forth in Koves, G. J. (Journal
of Radiolabeled Compounds and Radiopharmaceuticals (1991) 29(1) 15-22)
and Sternbach, L. H. et al. (Journal of Medicinal Chemistry, (1963) 6,
261-265) and is described in FIG. 4. The synthesis is a modification of
the protocol set forth in Example 1 with the only difference in the
synthetic details being the use of (U-13C2, 98%, 15N, 98%)
glycine (SM-3) as the amino acid precursor and
(2-amino-5-chloro)-benzophenone as the benzophenone precursor (SM-6).
Additionally, Clonazepam synthesis is complete upon cyclization to form
the diazepine ring system (i.e., conversion of I-26 to 4).

Example 5

Synthesis of 13C6-(2R,2'R)-(+)-Threomethylphenidate
Hydrochloride

[0210]The synthesis of isotope labeled methylphenidate was carried out
using a modification of the protocol set forth in Thai et al. (J. Med.
Chem. (1998), 41, 591-601) and is described in FIG. 5 and the following
written description.

Intermediate 27 (I-27)

[0211]Under a nitrogen atmosphere, a solution of
13C6-bromobenzene (SM-7) (37.98 mmol) in THF (25 mL) is to be
cooled to -78° C. To this mixture is added s-BuLi (32.1 mL, 41.78
mmol, 1.3 M in cyclohexane) over 20 min with the temperature maintained
at less than -50° C. The reaction mixture is aged for 15 min at
-78°. The solvent is removed under reduced pressure and the
residue is then redissolved in 20 μL hexanes to produce a 2 M solution
of I-27.

Intermediate 28 (I-28)

[0212]A solution of hydroxamate SM-8 (400 mg, 1.47 mmol) in Et2O (6.3
mL) is brought to -23° C. under an inert atmosphere, and a 2.0 M
solution of 13C6 phenyl lithium I-27 in hexanes (735
microliters, 1.47 mmol) is added dropwise via syringe over 15 min.
Stirring is continued at -23° C. for 3 h, after which the reaction
mixture is poured into an ice-chilled 1 M KH2PO4 solution (20
mL). The aqueous layer is extracted with EtOAc (4×15 mL), and the
combined EtOAc layer is dried, filtered, and evaporated. Chromatography
over silica gel eluting with 7.5-20% EtOAc in hexanes gives 200 mg of
ketone I-28 (47% yield) as well as 143 mg of recovered starting material
SM-8. Synthesis of SM-8 and the above conditions are described in: That
and co-workers, J. Med. Chem. (1998) 41, 591-601.

Intermediate 29 (I-29)

[0213]To a suspension of methyltriphenylphosphonium bromide (230 mg, 0.644
mmol) in THF (1.0 mL) is added solid potassium tert-butoxide (72.2 mg,
0.644 mmol), and the resulting yellow suspension is allowed to stir for
10 min. A solution of I-28 (124 mg, 0.429 mmol) in THF (2.0 mL) is then
added dropwise via syringe and the reaction allowed to proceed for 5 min.
The reaction is quenched with water (1.0 mL) and suspended between EtOAc
(15 mL) and water (15 mL). The aqueous layer is extracted with EtOAc
(2×15 mL). The combined EtOAc layers are dried, filtered, and
evaporated to an oil which is then filtered through a plug of silica gel
eluting with 9% EtOAc in hexanes to give 115 mg (93%) of I-29 as a
colorless oil. See That and co-workers, J. Med. Chem. (1998) 41, 591-601.

Intermediate 30 (I-30)

[0214]To a solution of I-29 (115 mg, 0.4 mmol) in THF (2.0 mL) is added
1.0 M BH3.THF (800 microliters, 0.8 mmol) dropwise at room
temperature via syringe over about 5 min. The reaction mixture is then
stirred for 4 h after which water (1.0 mL), 3 N NaOH (1.0 mL), and 30%
H2O2 (2.0 mL) are added consecutively. Stirring is continued
overnight. The resulting mixture is suspended between EtOAc (20 mL) and
water (15 mL), and the aqueous layer is extracted with EtOAc (3×10
mL). The combined EtOAc layers were dried, filtered, and evaporated to an
oil which is purified by silica gen chromatography eluting with 16-20%
EtOAc in hexanes. The less polar (1R,2R)-1-30 is obtained as a white
solid (78 mg, 64% yield). See That and co-workers, J. Med. Chem. (1998)
41, 591-601.

Intermediate 31 (I-31)

[0215]Alcohol I-30 (228 mg, 0.748 mmol) is dissolved in DMF (3.0 mL), and
PDC (984 mg, 2.62 mmol) is added. After 17 h of stirring, the reaction is
quenched with water (40 mL) and the resulting mixture extracted with
Et2O (6×20 mL). Combined Et2O layers are then extracted with
0.5 N NaOH (4×30 mL) and the alkaline solution brought to
pH=˜2.0 with 3 N HCl. A white precipitate is formed and is
extracted into EtOAc (4×30 mL) which is dried, filtered, and
evaporated under reduced pressure to give a crude colorless oil
containing the carboxylic acid I-31 (194 mg). See That and co-workers, J.
Med. Chem. (1998) 41, 591-601.

13C6-(2R,2'R)-(+)-threomethylphenidate 5

[0216]A portion (180 mg) of the crude oil I-31 is treated with excess
diazomethane in ether (10 mL). The solution is evaporated to a light
yellow oil which is stirred in 3 N methanolic HCl (10 mL) at room
temperature overnight. Evaporation under reduced pressure provides a
crude off-white solid which is recrystallized from EtOH/Et2O to give
125 mg of (2R,2'R)-5 as a white solid (67% yield from (1R,2R)-I-30).

Example 6

Synthesis of Deuterium Labeled Codeine

[0217]This example shows the synthesis of deuterium (D) labeled codeine
from Thebaine, a natural opioid that is produced in high quantities by
some varieties of Papaver somniferum (Blakemore P R, White J D, Chem.
Comm. 2002: 1159-1168). See FIG. 6.

D1-Codeinone O-2

[0218]A stirred solution of 100 g Thebain O-1 in CH2Cl2 (1 L) is
cooled to below 3° C. in an ice-salt bath and then rapidly
saturated with anhydrous DBr with continued cooling. The temperature is
kept below 15° C. by controlling the rate of DBr addition. The DBr
is added until the solution is saturated (˜35 min). as indicated by
a drop in temperature. The mixture is then cooled below 5° C. and
poured into cold, stirred saturated NaHCO3 solution (2 L). The
neutral mixture is adjusted to pH 12 by the addition of 50% NaOH
solution. The organic layer is separated and the aqueous phase washed
twice with CH2C12 (400 mL). The organic phases are combined, dried
over anhydrous Na2SO4 and the solvent is remove in vacuo to
leave a semicrystalline brown residue. The residue is triturated with
MeOH (100 mL) and chilled. The crystals are collected and washed with
three portions of cold MeOH (20 mL). These crystals are suspended in
H2O and, with warming and stirring, the mixture is adjusted to pH
1-2 by the addition of concentrated HCl. The clear yellow solution is
cooled in ice to 30° C., and 50% NaOH is added to give a thick
suspension (pH approx. 14). The suspension is cooled below 15° C.,
and the crystals are collected, pressed dry, and then washed with cold
water. The crystals should be dried overnight under high vacuum at 651C
to give 64.5 g (67%) of O-2.

[0219]To a solution of 194 mg of D1-codeinone O-2 in 10 ml methanol is
added 0.5 g sodium borodeuteride (NaBD4) which has been suspended in
12 ml methanol. The mixture is allowed to stand for 1.5 hours,
concentrated to 10 ml in vacuo and diluted with 10 ml of 10% sodium
hydroxide. The clear colorless solution is heated momentarily to boiling,
diluted with water and extracted four times with chloroform. The washed,
dried and filtered chloroform extract is then recrystallized from dilute
methanol to give an expected yield of 173 mg D2-Codeine (O-3). See Gates,
M. J. Am. Chem. Soc. (1953) 17, 4340-4341.

D1-Codeine (O-4)

[0220]To a solution of 194 mg of D1-codeinone O-2 in 10 ml methanol is
added 0.5 g sodium borohydride which has been suspended in 12 ml
methanol. The mixture is allowed to stand for 1.5 hours, concentrated to
10 ml in vacuo and diluted with 10 ml of 10% sodium hydroxide. The clear
colorless solution is heated momentarily to boiling, diluted with water
and extracted four times with chloroform. The washed, dried and filtered
chloroform extract is then recrystallized from dilute methanol to give an
expected yield of 173 ing D1-Codeine (O-4).

[0223]To a solution of O-5 (2.00 g, 6.38 mmol) in deuteroacetic acid
(CH3COOD) (10% in D2O, 40 mL) is added [Pd--BaSO4 (5%,
1.00 g)]. The catalyst is then filtered and washed with H2O and the
filtrate is made basic with concentrated NH4OH. The solution is
saturated with NaCl and extracted with CHCl3. The extracts are
washed with saturated NaCl solution and dried (MgSO4), and the
solvent is removed. The resulting crystalline solid is then washed with
Et20 and dried. Expected yield of O-6 is 1.91 g (95%). See Iijima,
I.; Minamikawa, J.; Jacobson, A. E.; Brossi, A.; Rice, K. C.; J. Med.
Chem. (1978) 21, 398.

(18O1)-hydroxycodeinone (O-7)

[0224]Thebaine O-1 (35 mg, 0.11 mmol) is combined with
meso-tetraphenylporphyrin (5,10,15,20-tetraphenyl-21H,23H-porphrine; TPP)
(5 mg, 0.03 mmol) in 50 mL of CH2Cl2. The solution is then
acidified with trifluoroacetic acid to pH=4. 18O oxygen
(18O2) is circulated through the solution in a round-bottomed
flask fitted with a cooling water-jacket [Currently >95% pure
18O2 is available from Cambridge Isotope Laboratories]. The
mixture is irradiated from a distance of 45 cm with an Osram
Ultra-Vitalux sun lamp (300 W) for 55 min. The mixture is concentrated to
20 mL under reduced pressure and then 50 mL of ethyl ether is added. The
resulting precipitate is decanted and washed with ethyl ether, affording
an expected 25 mg of the trifluoroacetate salt of O-7 (61% yield). See
Lopez, D.; Quinoa, E.; Riguera, R.; J. Org. Chem. (2000) 65(15)
4671-4678.

(D2,18O1)-oxycodone (O-8)

[0225]To a solution of O-7 (2.00 g, 6.38 mmol) in deuteroacetic acid
(CH3COOD) (10% in D2O, 40 mL) is added [Pd--BaSO4 (5%,
1.00 g)]. The solution is then placed under deuterium (D2) gas
atmosphere until the reaction is complete. The catalyst is then filtered
and washed with H2O and the filtrate is made basic with concentrated
NH4OH. The solution is saturated with NaCl and extracted with
CHCl3. The extracts are washed with saturated NaCl solution and
dried (MgSO4), and the solvent is removed. The resulting crystalline
solid then washed with Et2O and dried. Expected yield of O-8 is 1.91
g (95%). See Iijima, I.; Minamikawa, J.; Jacobson, A. E.; Brossi, A.;
Rice, K. C.; J. Med. Chem. (1978) 21, 398.

(18O1)-oxycodone (O-9)

[0226]To a solution of O-7 (2.00 g, 6.38 mmol) in acetic acid
(CH3COOH) (10% in H2O, 40 mL) is added [Pd-BaSO4 (5%, 1.00
g)]. The solution is then placed under hydrogen gas atmosphere (H2)
until the reaction is complete. The catalyst is then filtered and washed
with H2O and the filtrate is made basic with concentrated
NH4OH. The solution is saturated with NaCl and extracted with
CHCl3. The extracts are washed with saturated NaCl solution and
dried (MgSO4), and the solvent is removed. The resulting crystalline
solid O-9 is then washed with Et20 and dried. Expected yield of 0-9
is 1.91 g (95%). See Iijima, I.; Minamikawa, J.; Jacobson, A. E.; Brossi,
A.; Rice, K. C.; J. Med. Chem. (1978) 21, 398.

[0228]To a solution of O-2 (2.00 g, 6.4 mmol) in deuteroacetic acid
(CH3COOD) (10% in D2O, 40 mL) is added [Pd-BaSO4 (5%, 1.00
g)]. The solution is then placed under deuterium (D2) gas atmosphere
until the reaction is complete. The catalyst is then filtered and washed
with H2O and the filtrate is made basic with concentrated
NH4OH. The solution is saturated with NaCl and extracted with
CHCl3. The extracts are washed with saturated NaCl solution and
dried (MgSO4), and the solvent is removed. The resulting crystalline
solid O-10 is then washed with Et2O and dried. Expected yield of
O-10 is 1.9 g (95%). See Iijima, I.; Minamikawa, J.; Jacobson, A. E.;
Brossi, A.; Rice, K. C.; J. Med. Chem. (1978) 21, 398.

(D2)-hydrocodone (O-12)

[0229]To a solution of Codeinone O-11 (2.00 g, 6.4 mmol) in deuteroacetic
acid (CH3COOD) (10% in D2O, 40 mL) is added [Pd-BaSO4 (5%,
1.00 g)]. The solution is then placed under deuterium (D2) gas
atmosphere until the reaction is complete. The catalyst is then filtered
and washed with H2O and the filtrate is made basic with concentrated
NH4OH. The solution is saturated with NaCl and extracted with
CHCl3. The extracts are washed with saturated NaCl solution and
dried (MgSO4), and the solvent is removed. The resulting crystalline
solid O-12 is then washed with Et2O and dried. Expected yield of O-12 is
1.9 g (95%). See Iijima, I.; Minamikawa, J.; Jacobson, A. E.; Brossi, A.;
Rice, K. C.; J. Med. Chem. (1978) 21, 398.

(D1)-hydrocodone (O-13)

[0230]To a solution of (D1)-Codeinone O-2 (2.00 g, 6.4 mmol) in
acetic acid (CH3COOH) (10% in H2O, 40 mL) is added
[Pd-BaSO4 (5%, 1.00 g)]. The solution is then placed under hydrogen
(H2) gas atmosphere until the reaction is complete. The catalyst is
then filtered and washed with H2O and the filtrate is made basic
with concentrated NH4OH. The solution is saturated with NaCl and
extracted with CHCl3. The extracts are washed with saturated NaCl
solution and dried (MgSO4), and the solvent is removed. The
resulting crystalline solid O-13 is then washed with Et2O and dried.
Expected yield of O-13 is 1.9 g (95%). See Ijima, I.; Minamikawa, J.;
Jacobson, A. E.; Brossi, A.; Rice, K. C.; J. Med. Chem. (1978) 21, 398.

[0232]13CH3Br (a-1, 1.1 g, 11.7 mmol) is to be condensed into a
25 mL vacuum-line bulb. A dry ice/acetone condenser and a 100 mL Schlenk
flask containing Reade high-purity magnesium turnings (218 mg, 8.97 mmol)
are connected directly to a high-vacuum line through the side arm near
the base of the condenser. The apparatus is then evacuated and diethyl
ether (˜25 mL) is transferred into the reaction flask and
freeze-pump-thaw degassed. Before the final thawing the condenser is
charged with dry ice/acetone and an aliquot of 13CH3Br is
condensed into the reaction flask. The reaction mixture is allowed to
warm slowly to room temperature; stirring is to be started after bubbling
shows that the reaction has been initiated. The rest of the
13CH3Br is added in aliquots (using a mercury manometer to
control the addition) at a rate that maintains gental reflux of the
solution without external heating. After the addition is complete, the
reaction is stirred until all of the magnesium is consumed (˜1 h).
The diethyl ether and excess 13CH3Br is removed under reduced
pressure to yield a white crystalline product a-2, which is dried under
vacuum for 1 h. The product is extracted with diethyl ether (35 mL) and
filtered through a glass frit to give a clear, colorless solution
(˜0.36 M), which is used without further purification. See Bullock
R. M. and co-workers, J. Am. Chem. Soc. (1989), 111, 3897-3908.

Intermediate a-5 (15N--R-tert-butanesulfinamide)

[0233]A 5 L three-necked round bottomed flask equipped with a mechanical
stirrer, an ammonia condenser, and a nitrogen inlet is charged with 2 L
of liquid 15N-ammonia. A few crystals of Fe(NO3)3 are
added and lithium wire (13.3 g, 1.92 mol) is added in ca. 500 mg
portions. A -78 C bath is periodically raised to the bottom of the flask
to abate any refluxing caused by the formation of Li15NH2. As
lithium is added, the mixture will become blue, but fade to reveal a gray
suspension. When all the lithium wire is added and the mixture has become
gray, the flask is submerged into the -78 C bath. After 30 min a solution
of thiosulfinate a-3 (92.9 g, 0.479 mol) in 500 mL of THF is slowly added
over the course of an hour. Once the addition is complete the mixture is
stirred an additional 15 min before 128 g (2.40 mol) of NH4Cl is added
slowly and carefully. The cold bath is removed and stirring continued
until the mixture reaches ambient temperature. The remaining volatile
material is removed under aspirator pressure. To the remaining residue is
added 250 mL of water with swirling to dissolve all the salts. The
resulting mixture is extracted with 1.5 L of EtOAc (3×) and the
organic layers washed once each with the same 150 mL of brine before they
are combined and dried (Na2SO4). The solid remaining after removal of
solvent is recrystallized once from hexanes to provide an expected yield
of 45.6 g (79%) of enantiomerically pure
15N--R-tert-butanesulfinamide a-5. The synthesis of thiosulfinate
a-3 and reaction with lithium amide is described in Liu, G. Cogan, D. A.,
Ellman, J. A. J. Am. Chem. Soc. (1997), 119, 9913-9914.

[0234]To a solution of 15N-tert-butanesulfinamide a-5 (0.12 g, 1.0
mmol) and phenyl-acetaldehyde a-6 (1.2 mmol) in CH2Cl2 (2.5 mL)
is added titanium tetraethoxide (purity: 85-95%, 0.46 mL, 2 mmol) under a
nitrogen atmosphere. The mixture is stirred at room temperature for 15 h.
Diatomaceous earth (8 mL) is placed in a polypropylene SPE cartridge (12
mL, with 70 micrometer PE frit) equipped with a PTFE stopcock and then is
soaked with water (2.5 mL). The reaction mixture is then to be
transferred to the SPE cartridge while rinsing with 5 mL of
CH2Cl2, and the cartridge is plugged with a glass stopper
coated with PTFE seal tape. The cartridge is shaken vigorously for 30 s
so that the diatomaceous earth flows freely in the cartridge. The mixture
is shaken for 30 min with a wrist action shaker. During the mixing, the
cartridge is shaken vigorously with hands at intervals to ensure
effective mixing. The solid phase is filtered and washed with
CH2Cl2 until no product can be found in the elution. The
filtrate is evaporated and filtered through a 0.5-cm plug of silica gel
(Merck 60 230-400 mesh) in a glass pipet. The silica gel is washed with a
small amount of a 9:1 CH2Cl2/Et2O mixture. The product
imine a-7 (1.0 mmol) contaminated with excess aldehyde will be obtained
by evaporation of the solvent from the filtrate. See Mukade, T. Dragoli,
D. R. Ellman, J. A., J. Comb. Chem. (2003), 5, 590-596.

[0235]The mixture containing 1 mmol of imine a-7 is dissolved in
CH2C12 (5 mL) and cooled to -48 C. To this cooled mixture,
13CH3MgBr a-2 in diethyl ether (3.0 M, 0.800 mL, 2.40 mmol) is
added slowly dropwise. The reaction mixture is stirred at -48 C for 6 h
and then is allowed to gradually warm to room temperature. After stirring
overnight, the reaction is quenched by the addition of saturated aqueous
ammonium chloride solution (2 mL). After stirring vigorously for 10 min,
the mixture is transferred to a 1PS filter cartridge equipped with a PTFE
stopcock, and the organic phase is isolated. The aqueous phase is rinsed
with dichloromethane (3×2 mL) and evaporated to afford the desired
crude sulfonamide product a-8 (expected yield 77% with 91% ee). The
product a-8 is used without further purification. See Mukade, T. Dragoli,
D. R. Ellman, J. A., J. Comb. Chem. (2003), 5, 590-596.

Intermediate a-9 (13C,15N-dextroamphetamine)

[0236]The product a-8 (0.77 mmol) is dissolved in methanol (2 mL). To this
mixture is added 4 N hydrogen chloride in 1,4-dioxane (2 mL). The mixture
is stirred for 30 min and then concentrated to dryness. The obtained
mixture is distributed in 0.5 N hydrochloric acid (2 mL) and
dichloromethane (2 mL) and is then transferred to a 1PS filter cartridge
(12 mL) equipped with a PTFE stopcock. The organic layer is removed, and
the aqueous layer is washed with CH2Cl2 (3×2 mL). A 2 N
sodium hydroxide solution (2 mL) is then added to the aqueous layer, and
the resulting free amine was extracted with dichloromethane (3×2
mL). The solvent is then removed under reduced pressure to obtain a-9.
See Mukade, T. Dragoli, D. R. Ellman, J. A., J. Comb. Chem. (2003), 5,
590-596.

[0238]A 5 L three-necked round bottomed flask equipped with a mechanical
stirrer, an ammonia condenser, and a nitrogen inlet is charged with 2 L
of liquid 15N-ammonia. A few crystals of Fe(NO3)3 are
added and lithium wire (13.3 g, 1.92 mol) is added in ca. 500 mg
portions. A -78 C bath is periodically raised to the bottom of the flask
to abate any refluxing caused by the formation of Li15NH2. As
lithium is added, the mixture will become blue, but fade to reveal a gray
suspension. When all the lithium wire is added and the mixture has become
gray, the flask is submerged into the -78 C bath. After 30 min a solution
of thiosulfinate a-10 (92.9 g, 0.479 mol) in 500 mL of THF is slowly
added over the course of an hour. Once the addition is complete the
mixture is stirred an additional 15 min before 128 g (2.40 mol) of
NH4Cl is added slowly and carefully. The cold bath is removed and
stirring continued until the mixture reaches ambient temperature. The
remaining volatile material is removed under aspirator pressure. To the
remaining residue is added 250 mL of water with swirling to dissolve all
the salts. The resulting mixture is extracted with 1.5 L of EtOAc
(3×) and the organic layers washed once each with the same 150 mL
of brine before they are combined and dried (Na2SO4). The solid
remaining after removal of solvent is recrystallized once from hexanes to
provide an expected yield of 45.6 g (79%) of enantiomerically pure
15N--S-tert-butanesulfinamide a-11. The synthesis of thiosulfinate
a-10 and reaction with lithium amide is described in Liu, G. Cogan, D.
A., Ellman, J. A. J. Am. Chem. Soc. (1997), 119, 9913-9914.

[0239]To a solution of 15N-tert-butanesulfinamide a-11 (0.12 g, 1.0
mmol) and phenyl-acetaldehyde a-6 (1.2 mmol) in CH2Cl2 (2.5 mL)
is added titanium tetraethoxide (purity: 85-95%, 0.46 mL, 2 mmol) under a
nitrogen atmosphere. The mixture is stirred at room temperature for 15 h.
Diatomaceous earth (8 mL) is placed in a polypropylene SPE cartridge (12
mL, with 70 micrometer PE frit) equipped with a PTFE stopcock and then is
soaked with water (2.5 mL). The reaction mixture is then to be
transferred to the SPE cartridge while rinsing with 5 mL of
CH2Cl2, and the cartridge is plugged with a glass stopper
coated with PTFE seal tape. The cartridge is shaken vigorously for 30 s
so that the diatomaceous earth flows freely in the cartridge. The mixture
is shaken for 30 min with a wrist action shaker. During the mixing, the
cartridge is shaken vigorously with hands at intervals to ensure
effective mixing. The solid phase is filtered and washed with
CH2Cl2 until no product can be found in the elution. The
filtrate is evaporated and filtered through a 0.5-cm plug of silica gel
(Merck 60 230-400 mesh) in a glass pipet. The silica gel is washed with a
small amount of a 9:1 CH2C12/Et2O mixture. The product imine
a-12 (1.0 mmol) contaminated with excess aldehyde will be obtained by
evaporation of the solvent from the filtrate. See Mukade, T. Dragoli, D.
R. Ellman, J. A., J. Comb. Chem. (2003), 5, 590-596.

[0240]The mixture containing 1 mmol of imine a-12 is dissolved in
CH2C12 (5 mL) and cooled to -48 C. To this cooled mixture,
13CH3MgBr a-2 in diethyl ether (3.0 M, 0.800 mL, 2.40 mmol) is
added slowly dropwise. The reaction mixture is stirred at -48 C for 6 h
and then is allowed to gradually warm to room temperature. After stirring
overnight, the reaction is quenched by the addition of saturated aqueous
ammonium chloride solution (2 mL). After stirring vigorously for 10 min,
the mixture is transferred to a 1PS filter cartridge equipped with a PTFE
stopcock, and the organic phase is isolated. The aqueous phase is rinsed
with dichloromethane (3×2 mL) and evaporated to afford the desired
crude sulfonamide product a-13 (expected yield 77% with 91% ee). The
product a-13 is used without further purification. See Mukade, T.
Dragoli, D. R. Ellman, J. A., J. Comb. Chem. (2003), 5, 590-596.

a-14 (13C,15N-levamphetamine)

[0241]The product a-13 (0.77 mmol) is dissolved in methanol (2 mL). To
this mixture is added 4 N hydrogen chloride in 1,4-dioxane (2 mL). The
mixture is stirred for 30 min and then concentrated to dryness. The
obtained mixture is distributed in 0.5 N hydrochloric acid (2 mL) and
dichloromethane (2 mL) and is then transferred to a 1PS filter cartridge
(12 mL) equipped with a PTFE stopcock. The organic layer is removed, and
the aqueous layer is washed with CH2Cl2 (3×2 mL). A 2 N
sodium hydroxide solution (2 mL) is then added to the aqueous layer, and
the resulting free amine was extracted with dichloromethane (3×2
mL). The solvent is then removed under reduced pressure to obtain a-14.
See Mukade, T. Dragoli, D. R. Ellman, J. A., J. Comb. Chem. (2003), 5,
590-596.

Examples 11-14

Synthesis of Mono-Labeled Amphetamines

##STR00038##

[0242]Example 11

(13C-dextroamphetamine) a-15

[0243]Prepare as described above for a-9 but use unlabeled NH3 rather
than 15NH3.

Example 12

(13C-levamphetamine) a-16

[0244]Prepare as described above for a-14 but use unlabeled NH3
rather than 15NH3.

Example 13

(15N-dextroamphetamine) a-17

[0245]Prepare as described above for a-9 but use unlabeled CH3Br
rather than 13CH3Br.

Example 14

(15N-levamphetamine) a-18

[0246]Prepare as described above for a-14 but use unlabeled CH3Br
rather than 13CH3Br.

[0259]This example describes the synthesis of
13C,15N-methamphetamine. See FIG. 11(a).

[0260]The amphetamine a-9 (10 mmol) is combined with 3.33 mmol
para-formaldehyde in 50 mL dry benzene. The mixture is placed in a round
bottom flask affixed with a Dean-Stark trap. The mixture is refluxed for
two hours with continuous removal of water. The benzene is then removed
using reduced pressure. To the residue is added 50 mL dry Et2O and
an excess of LiAlH4 is slowly added. The mixture is stirred for one
hour at room temperature. The reaction is quenched slowly with water, and
extracted with CH2Cl2. The organic layer is dried using
anhydrous MgSO4 and evaporated to produce labeled methamphetamine
a-19. See Bartroli and co-workers, J. Med. Chem. (1998), 41, 1855-1868;
Konosu and coworkers, Chem. Pharm. Bull. (1991), 39, 2581-2589.

Example 28

(13C-methamphetamine) a-20

[0261]This example describes the synthesis of 13C-methamphetamine.
See FIG. 11(b). Prepare as described above for a-19 but start with a-15.

Example 29

(15N-methamphetamine) a-21

[0262]This example describes the synthesis of 15N-methamphetamine.
See FIG. 11(c). Prepare as described above for a-19 but start with a-17.

[0266]All apparatus are dried and the reaction is carried out under an
inert atmosphere of argon. A solution of
(R)-(-)-2,2-diphenyl-4-dimethylaminopentanenitrile m-5 (5.0 g, 0.018 mol)
in toluene (15 mL) is added to a stirred solution of 3 M
13C-ethylmagnesium bromide m-2 in ether (10.7 mL, 0.03 mol). The
ether is removed under reduced pressure and the remaining solution is
heated at reflux (135-140° C.) for 3 h. The solution will go
slightly cloudy. After cooling to room temperature 2N HCl (30 mL) is
added with care and then stirring is continued at 135-140° C.) for
a further 30 min. The two phases are allowed to separate and cool to room
temperature. After scratching the sides of the flask, a solid will start
to crystallize from the aqueous phase. The flask should be cooled to
complete crystallization and the white solid collected by filtration.
This solid is then recrystallized from water to yield 2.7 g (43%) of
(R)-(-)-methadone hydrochloride m-6. See Hull and co-workers,
Tetrahedron: Asymmetry (2003), 14, 567-576 for a description of the
synthesis of m-5.

Example 31

D3-R-(-)-methadone (m-7)

[0267]As described above for 13C--R-(-)-methadone m-6 but substitute
D3-ethylmagnesium bromide m-4 in place of 13C-ethylmagnesium bromide
m-2. See Hull and co-workers, Tetrahedron. Asymmetry (2003), 14, 567-576]

[0269]Double 2H labeled morphine can be prepared using a modification
of the procedure described in Journal of Medicinal Chemistry, 1977, vol
20, 164-165. A solution of 2.99 g (10 mmol) of anyhydrous D2-Codiene O-3
in 25 ml of CHCl3 is to be added during 2 min to a well-stirred
solution of 15 g (59.9 mmol) of BBr3 in 175 ml of CHCl3
maintained in the range 23-26 degrees C. A 10 ml portion of CHCl3,
which is added to rinse the addition funnel, is added to the reaction
mixture and stirring is continued for 15 min at 23-26 degrees C. The
reaction mixture which will consist of a suspension of white solid (in
CHCl3) is then poured into a well-stirred mixture of 80 g of ice and
20 ml of concentrated (28-30% NH3) NH4OH. The two-phase system
is kept at -5 to 0 degrees C. for 0.5 h (continuous stirring) and
filtered. The resulting crystalline material is washed thoroughly with
small portions of cold CHCl3 and H2O and dried to give 2.67 g
(88.1%) of slightly off-white MO-3 monohydrate.

Example 33

D1-Morphine (MO-4)

[0270]Single 2H labeled morphine can be prepared using a modification
of the procedure described in Journal of Medicinal Chemistry, 1977, vol
20, 164-165. A solution of 2.99 g (10 mmol) of anyhydrous D2-Codiene O-3
in 25 ml of CHCl3 is to be added during 2 min to a well-stirred
solution of 15 g (59.9 mmol) of BBr3 in 175 ml of CHCl3 maintained
in the range 23-26 degrees C. A 10 ml portion of CHCl3, which is
added to rinse the addition funnel, is added to the reaction mixture and
stirring is continued for 15 min at 23-26 degrees C. The reaction mixture
which will consist of a suspension of white solid (in CHCl3) is then
poured into a well-stirred mixture of 80 g of ice and 20 ml of
concentrated (28-30% NH3) NH4OH. The two-phase system is kept
at -5 to 0 degrees C. for 0.5 h (continuous stirring) and filtered. The
resulting crystalline material is washed thoroughly with small portions
of cold CHCl3 and H2O and dried to give 2.67 g (88.1%) of
slightly off-white MO-3 monohydrate.

[0272]Triple 2H labeled hydromorphone can be prepared using a
modification of the procedure described in Journal of Medicinal
Chemistry, 1977, vol 20, 164-165 and Tetrahedron Letters Vol. 25,
3335-3338, 1984. A solution of 2.99 g (10 mmol) of anyhydrous
D2-Hydrocodone O-10 in 25 ml of CHCl3 is to be added during 2 min to
a well-stirred solution of 15 g (59.9 mmol) of BBr3 in 175 ml of
CHCl3 maintained in the range 23-26 degrees C. A 10 ml portion of
CHCl3, which is added to rinse the addition funnel, is added to the
reaction mixture and stirring is continued for 15 min at 23-26 degrees C.
The reaction mixture which will consist of a suspension of white solid
(in CHCl3) is then poured into a well-stirred mixture of 80 g of ice
and 20 ml of concentrated (28-30% NH3) NH4OH. The two-phase
system is kept at -5 to 0 degrees C. for 0.5 h (continuous stirring) and
filtered. The resulting crystalline material is washed thoroughly with
small portions of cold CHCl3 and H2O and dried to give 2.67 g
(88.1%) of slightly off-white MO-10 monohydrate.

Example 35

D2-Hydromorphone (MO-12)

[0273]Double 2H labeled hydromorphone can be prepared using a
modification of the procedure described in Journal of Medicinal
Chemistry, 1977, vol 20, 164-165 and Tetrahedron Letters Vol. 25,
3335-3338, 1984. A solution of 2.99 g (10 mmol) of anyhydrous
D2-Hydrocodone O-12 in 25 ml of CHCl3 is to be added during 2 min to
a well-stirred solution of 15 g (59.9 mmol) of BBr3 in 175 ml of
CHCl3 maintained in the range 23-26 degrees C. A 10 ml portion of
CHCl3, which is added to rinse the addition funnel, is added to the
reaction mixture and stirring is continued for 15 min at 23-26 degrees C.
The reaction mixture which will consist of a suspension of white solid
(in CHCl3) is then poured into a well-stirred mixture of 80 g of ice
and 20 ml of concentrated (28-30% NH3) NH4OH. The two-phase
system is kept at -5 to 0 degrees C. for 0.5 h (continuous stirring) and
filtered. The resulting crystalline material is washed thoroughly with
small portions of cold CHCl3 and H2O and dried to give 2.67 g
(88.1%) of slightly off-white MO-12 monohydrate.

Example 36

D1-Hydromorphone (MO-13)

[0274]Double 2H labeled hydromorphone can be prepared using a
modification of the procedure described in Journal of Medicinal
Chemistry, 1977, vol 20, 164-165 and Tetrahedron Letters Vol. 25,
3335-3338, 1984. A solution of 2.99 g (10 mmol) of anyhydrous
D2-Hydrocodone O-13 in 25 ml of CHCl3 is to be added during 2 min to
a well-stirred solution of 15 g (59.9 mmol) of BBr3 in 175 ml of
CHCl3 maintained in the range 23-26 degrees C. A 10 ml portion of
CHCl3, which is added to rinse the addition funnel, is added to the
reaction mixture and stirring is continued for 15 min at 23-26 degrees C.
The reaction mixture which will consist of a suspension of white solid
(in CHCl3) is then poured into a well-stirred mixture of 80 g of ice
and 20 ml of concentrated (28-30% NH3) NH4OH. The two-phase
system is kept at -5 to 0 degrees C. for 0.5 h (continuous stirring) and
filtered. The resulting crystalline material is washed thoroughly with
small portions of cold CHCl3 and H2O and dried to give 2.67 g
(88.1%) of slightly off-white MO-13 monohydrate.

[0276]D6-Zolpidem can be prepared using a modification of the procedure
described in U.S. Pat. No. 6,281,360. Suspend 5 g of
2-(p-tolyl)-6-methylimidazo[1,2a]pyridine-3-acetic acid zo1 in 50 ml of
dry dichloromethane and add 2.5 g of oxalylchloride. Then, add slowly
under stirring 5 drops of dimethylformamide (gas formation occurs) and,
after 3 hours, add 1.1 g of oxalylchloride. Stir the reaction mixture for
1 hour then bubble slowly gaseous NH(CD3)2 through the reaction
mixture for 1.5 hours. After termination, wash the reaction mixture with
2×10 ml of water, dry the organic phase with sodium sulfate and
evaporate the solvent under reduced pressure. After adding 25 ml of ethyl
acetate to the rest, a solid precipitates. Filter off the precipitate,
wash with 2×5 ml of ethyl acetate and dry in a vacuum oven at 40
degrees C. The yield should be 4.3 g of z02.

Example 38

Synthesis of 15N,13C-Zolpidem, (z04)

[0277]15N,13C-Zolpidem can be prepared using a modification of the
procedure described in U.S. Pat. No. 6,281,360 and Tetrahedron 58 (2002)
8779-8791. Suspend 5 g of
2-(p-tolyl)-6-methylimidazo[1,2a]pyridine-3-acetic acid zo1 in 50 ml of
dry dichloromethane and add 2.5 g of oxalylchloride. Then, add slowly
under stirring 5 drops of dimethylformamide (gas formation occurs) and,
after 3 hours, add 1.1 g of oxalylchloride. Stir the reaction mixture for
1 hour then bubble slowly gaseous 15NH2CH3 through the
reaction mixture for 1.5 hours. After termination, wash the reaction
mixture with 2×10 ml of water, dry the organic phase with sodium
sulfate and evaporate the solvent under reduced pressure. After adding 25
ml of ethyl acetate to the rest, a solid precipitates. Filter off the
precipitate, wash with 2×5 mil of ethyl acetate and dry in a vacuum
oven at 40 degrees C. The yield should be 4.3 g of z03.

[0278]To a solution of zo3 (1.63 mmol) in DMF will be added
13CH31 (2.4 mmol) and 55 wt % of NaH (2.0 mmol) at 0 degrees C.
After stirring for 3 h, the reaction mixture is quenched with sat.
NH4Cl (2 ml). The resulting mixture will be diluted with ether and
washed with water and brine, dried over MgSO4 and filtered. The
filtrate will be evaporated in vacuo to give 508 mg of a crude product,
which will be purified by silica gel column chromatography.

[0279]D6-Zolpidem hemitartrate and 15N, 13C-zolpidem hemitartrate can be
prepared using a modification of the procedure described in U.S. Pat. No.
6,281,360. Dissolve 1 g of labeled zolpidem in 10 ml of methanol and add
a solution of 0.244 g of L-tartaric acid in 5 ml of methanol. After
cooling, white crystals are formed. Collect the solid by filtration, wash
with cold methanol and dry.

Example 41

Synthesis of Deuterated Buprenorphine

[0280]This example describes the synthesis of deuterated buprenorphine.
See FIG. 16. Deuterated buprenorphine can be prepared using a
modification of the procedure described in GB1136214 and U.S. Pat. No.
3,433,791. Dissolve 40 g of bbl in ethanol (300 ml) and deuterate it with
D2 gas in the presence of Raney nickel catalyst (10 g) at 161-164
celsius and 164-182 atmosphere for four hours. Concentrate the solution
after removing the catalyst by filtration will afford a white crystalline
solid (26 g). This material is recrystallized from ethanol.

[0282]Various labeled tramadols can be prepared using a modification of
the procedure described in Tetrahedron Letters 41 (2000) 6635-6638 and J.
Org. Chem. 39, (1974) 3875-3877.

Methylated Hydroxylamine Resin t4:

[0283]To 2 g hydroxylamine resin t1 (0.5 mmol/gram loading) is added 2
mmol Boc anhydride and 2 mmol diisopropylethylamine in 10 ml THF and
stirred for one hour. The resin is filtered and washed with
dimethylformamide three times. To the resin is added 20 mmol NaH in
dimethylformamide and the suspension is stirred for 16 h at room
temperature. A quantity of 40 mmol of the labeled alkyl iodide R1I
is then added and stirred for another 16 h. The solution is filtered from
the resin and the resin is washed with dimethylformamide several times.
The resin is then treated with 20% trifluoroacetic acid in
dichloromethane for 30 min after which it is filtered and washed three
times with dimethylformamide. This will yield 1 mmol t4 on resin.

Labeled Tramadol t10:

[0284]To 2 g of methylated hydroxylamine resin t4 (1 mmol) is added 2 mmol
trimethylsilyl chloride and 2 mmol triethylamine in 10 ml
tetrahydrofuran. This suspension is stirred for one hour at room
temperature. A quantity of 2 mmol chloromethylethyl ether is added to the
suspension and stirred for 30 min at room temperature. Finally 2 mmol of
cyclohexanone trimethylsilyl enol ether is added to the suspension and
stirred for another hour at room temperature. The resin is then filtered
and washed three times with tetrahydrofuran. The resin bound ketone t6 is
then reacted with 3-methoxyphenyl magnesium bromide (10 mmol in 50 ml
tetrahydrofuran) at room temperature for 16 h to give tertiary alcohol
t8. The resin is then filtered and washed three tines with THF and three
times with dichloromethane. The resin is then treated with labeled
R20SO2CF3 in dichloromethane (5 mmol
R2OSO2CF3 in 20 ml dichloromethane) for 16 h at room
temperature. Finally the resin is treated with 5 mmol triethylamine in 20
ml dichloromethane at room temperature for 16 h to cleave the labeled
tramadol t10 from the resin. The resin is filtered and the filtrate is
dried under vacuum and purified by chromatography.

Labeled Methyl-Trifluorosulfonate:

[0285]Labeled methyl iodide (1 mmol) is added with stirring to 0.259 g (1
mmol) of silver triflate in 3 ml of carbon tetrachloride at ambient
temperature. The solid silver iodide is filtered off and the labeled
methyl triflate is isolated by removing the carbon tetrachloride in
vacuo.

Example 42

Synthesis of 13C-Tramadol

[0286]Follow the above procedures, use CH3I for R1I and
13CH3I for R2I.

Example 43

Synthesis of 13C2-Tramadol

[0287]Follow the above procedures, use 13CH3I for R1I and
13CH3I for R2I.

Example 44

Synthesis of D3-Tramadol

[0288]Follow the above procedures, use CH3I for R1I and
CD3I for R2I.

Example 45

Synthesis of 13C,D3-Tramadol

[0289]Follow the above procedures, use CH3I for R1I and
13CD3I for R2I.

Example 46

Synthesis of 13C2,D3-Tramadol

[0290]Follow the above procedures, use 13CH3I for R1I and
13CD3I for R2I.

REFERENCES CITED

[0291]Numerous references, including patents, patent applications and
various publications, are cited and discussed in the description of this
invention. The citation and/or discussion of such references is provided
merely to clarify the description of the present invention and is not an
admission that any such reference is "prior art" to the invention
described herein. All references cited and discussed in this
specification are incorporated herein by reference in their entirety and
to the same extent as if each reference was individually incorporated by
reference.